Motorcycle Accident-Prone Types at Intersections and Innovative Improvement Design Guideline

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1 Motorcycle Accident-Prone Types at Intersections and Innovative Iproveent Design Guideline Hsu,Tien-Pen a, Ku-Lin Wen b a,b Departent of Civil Engineering, National Taiwan University, Taipei, 6, Taiwan a E-ail: hsutp@ntu.edu.tw b E-ail: wengulin@ntu.edu.tw Abstract: In the past, traffic engineering designs are ostly based on car traffic volue, delay, and travel tie and efficiency oriented. However, the traffic coposition and traffic volue of otorcycle are very high in Taiwan and in soe Asia countries as well. The traffic engineering design ust take otorcycles into consideration. Besides, proportion of otorcycle in the accident casualty is also very high, and furtherore, the nuber of otorcycle causality is increasing in recent year. In the past, the segregated flow concept to substitute for ixed traffic has been ipleented and has caused the decrease of the death accident. However, the injured accidents is still increasing continuously. Therefore, the study ais at analyzing the accident data using collision diagra and an accident diagnosis process to find out the traffic engineering design proble and to propose the new design ethod for reducing otorcycle involved accidents. Keywords: Accident, Motorcycle, Traffic Safety, Collision Diagra, Traffic Flow Dynaic. INTRODUCTION The Decade of Action for Road Safety 2 22 was proclaied by the United Nations General Assebly in 2(United Nations 2). Every country tries to iprove road safety by different polices. However, Taiwan s traffic safety environent becoe worsening in recent years. Fro last ten year (23~23) statistics shows that the growing rate of registration nuber of car and otorcycle is.95% and.55% respectively. However, the growth rate of accidents of car and otorcycle is 4.26% and 2.64% respectively. The nuber of otorcycle accidents increase ore significantly. Accident data shows that in the collision between otorcycle and car the ain injured group is otorcycle rider. Therefore, the research focuses on iproveent of otorcycle safety, in order to prevent collision between otorcycle and other road users. Figure shows the vehicle nuber and accident data in recent years.

2 Vehicle(,) 6, 4, 2,, 8, 6, 4, 2, private car() 5,72 5,263 5,496 5,556 5,568 5,53 5,559 5,643 5,787 5,99 6,47 otorcycle () 2,3672,7943,953,5573,9434,3654,644,8455,745,44,95 car (A+A2) otorcycle (A+A2) Figure. Vehicle and accident data during 23~23(sources: Institute of Transportation 23) Resulting fro the analysis of accident data of recent three years, the otorcycle accident sites are ostly located at intersection or near intersection, about 49%, as shown in Figure 2. In Taiwan, now a day, otorcycle traffic safety facilities basically contained two-stage left turn waiting zone, otorcycle waiting zone, perissive otorcycle lane, and exclusive otorcycle lane etc. in the past. Although these design ethods could separate otorcycle fro the other car traffic flow and could be expected to reduce the accident between the otorcycle and car. The deaths nuber of accidents is reduced. However, the otorcycle injury nuber is still increasing. It iplicates soe accident probles are unclear. The study would apply traffic flow dynaic analysis and collision diagra ethod to investigate these probles. Then, a new otorcycle safety design guideline was proposed accordingly. 2~23 Accident Location Analysis 6.% 5.% 4.% 3.% 2.%.%.% Vehicle Accident Motorcycle Accident Figure 2. Accident location analysis of otorcycle accident in Taiwan

3 2. LITERATURE REVIEW In order to conduct analyzing accidents at intersection and proposing design ethods, the study would briefly review the researches of otorcycle traffic facility in operation, otorcycle traffic characteristics in the past. In soe Asian countries, such as Vietna, Thailand etc. they also have large nuber of otorcycles. Their ajor accident fatality group is still the otorcyclist, siilar with the situation in Taiwan (Hsu 24, Ponboon etc. 2, Nguye 24). However, in these countries they have not the sae countereasures like segregate flow at intersections in Taiwan, even the traffic probles raised by otorcycle are siilar in every country (APEC Transportation Working Group 2, Hsu 24 ). 2. Segregated Flow Design for Motorcycle The segregated flow design countereasures ipleented in Taiwan consists of otorcycle exclusive lane, otorcycle waiting zone, two-stage left turn of otorcycle etc. (Hsu 998). Because otorcycle is the ain travel ode in Taiwan, overall traffic syste should provide reasonable space and suitable traffic facilities exclusive for otorcycle. The ain otorcycle traffic iproveent principles in Taiwan in the past include:. Installing traffic island or arking to separate otorcycle fro other otorized vehicles. 2. Providing head start waiting zone for otorcycle to depart before the car at intersection. 3. Two stage left-turn regulation for otorcycle. 4. Traffic regulation facility should be designed for vehicle and otorcycle differently. 2.2 Motorcycle Traffic Characteristics The otorcycle traffic characteristics could be concluded generally as follows:. Waiting and departure characteristic at intersection In Taiwan, otorcycle rides on the right side of the road. Most otorcycles ove forward to the stop line as close as possible and then to wait during red tie at otorcycle waiting zone at intersection. Motorcycles would stop over the stop line due to the layout of two-stage leftturn waiting zone (Hsu, et al. 994). Coparing the difference of departure characteristics under with and without head start waiting zone for otorcycle, the results depict that the total delay at intersection would decrease and the departure rate would increase under provision of two stage otorcycle waiting zone and head start waiting zone for otorcycle (Hsu, et al. 998). 2. Motorcycle s passenger car equivalent and traffic capacity characteristics Generally speaking, the otorcycle s passenger car equivalent (PCE) is.3 in Taiwan Highway Capacity Manual (Institute of Transportation 2). However, the otorcycle s PCE would decrease when the otorcycle s ixture coposition increases (Hsu 996, Institute of Transportation 2). 2.3 Motorcycle Traffic Safety The ain reason for the rapid increasing nuber of otorcycle accidents is not only the increasing nuber of otorcycle ownership and/or otorcyclist behavior, but also the lack of effective otorcycle traffic facility for enhancing otorcycle traffic safety. Besides, otorcycle

4 accidents often are caused by the influence of local street environent, the characteristic of intersection layout and traffic oveent characteristics of various vehicles. Therefore, how to find out the better traffic engineering design countereasures is one of the ost iportant issues for the countries with high otorcycle traffic volue. 3. ACCIDENT-PRONE INTERSECTION ANALYSIS The study selected several accident-prone intersections to draw the accident collision diagras in order to identify the ain accident types at intersections. After that, traffic flow dynaic analysis ethod is used to analyze traffic conflicts related to the accident types. Fro the result of traffic flow dynaic analysis and accident diagnosis based on collision diagra, the causes of accidents are identified. Based on it, various safety iproveent countereasures are proposed. Finally, the study developed a new otorcycle safety design guideline. The flow chart of the study is shown in Figure 3. Define research scope Reference review Motorcycle accident analysis Accidentprone intersection analysis Traffic flow analysis Yellow tie and red tie design analysis Collision diagra analysis Accident diagnosis Motorcycle traffic safety design guideline at intersection Iproveent design ethod Conclusions and Recoendations Figure 3. Research flow chart to develop new otorcycle safety design guide 3. Accident Investigation Method By using the accident diagnosis analysis based on collision diagra, the relationship between accident and geoetry design and traffic engineering countereasures at intersection could be identified. The process for generating collision diagra contains drawing geoetric layout

5 condition diagra of intersection and accident collision diagra. The intersection condition diagra shows the geoetry design, control facility, road type, signal tiing, signal head location etc. Accident collision diagra illustrates different collision types at different locations at intersection. Besides, it also shows the accident consequence, road situation, light situation etc. By using special sybol cobination could ark each accident at the intersection clearly. The collision legends are shown in appendix. 3.2 Traffic Flow Dynaic Analysis The research applied video recording ethod to get field traffic flow data, and then using digitalized iage ethod to count the traffic flow dynaic trace at intersection. After that, the research could get the otorcycle and car traffic flow variation of position, velocity, and acceleration, especially with respect to the conflict situation. The process using iage processing and digitalized ethod to get the data is shown in Figure 4. Find appropriate location and tie for video recording Getting the geoetric easureent of intersection Recording traffic flow Traffic flow data analysis Collect vehicle Teperal-spatial data by software Transfor digital video into digitalized iages Figure 4. Traffic flow field survey procedure 3.3 Method for Creating Iproveent Street Design Countereasures The safety enhanceent design countereasures are generated fro accident diagnosis of the collision diagra at intersections. Fro collision diagra, the ain otorcycle collision types would be identified. Then, the study has discussed the causes of each ain collision type, including the factors of environent, geoetry design, traffic control, and traffic characteristic etc. 4. MAJOR SAFETY PROBLEMS AT ACCIDENT-PRONE INTERSECTIONS Fro accident statistics analysis using the data bank of national accident data(institute of Transportation 23), the ajor collision types between car and otorcycle are turning oveent other angle collision (4.4%), sae direction s sideswiped collision (4.2%), rightangle collision (3.4%), rear-end collision (.7%) etc. It shows that existing otorcycle facility at intersection can t solve the proble of the increase of accident nuber involved by otorcycle. Therefore, the study would find out the conflict probles at intersection by traffic flow dynaic analysis. 4. Left Turn Conflict Analysis Taking the intersection of Zhong-zheng Rd. /New Taipei Rd. in New Taipei City as case (Institute of Transportation 24), the southwest bound of the intersection occurred a lot of leftturn other angle collisions of otorcycle crashed against the straight car at sae direction. Resulting fro field traffic survey, there are 2.8% of otorcyclists ake the direct left turn illegally, but not follow the two stage left turn regulation rule at the intersection. Therefore, the collisions between illegal left-turn otorcycles and other straight vehicles occurred frequently,

6 as shown in Figure 5. It illustrates a typical proble of otorcycle left turn regulation. New Taipei Rd. Zhongzheng Rd. Zhongzheng Rd. Long An Rd. Figure 5. Exaple of collision diagra of Intersection of Zhongzheng Rd. /New Taipei Rd. Furtherore, in soe other sall intersections, there is usually not two-stage left turn regulation for otorcycle. Left turn otorcycle is allowed to ake left turn directly. However, under this situation, soe otorcycles are used to ride on the curb side lane to ake left turn. It will cause the conflict with the straight traffic. Because current guideline doesn t provide the design ethod for otorcycle direct left turn at such type of intersection, the research would investigate and propose new countereasures to ake otorcycle direct left-turn safer. 4.2 Conflict of Right Turning Traffic and Straight Traffic Taking Intersection of Zhongzheng N. Rd. / Chongyang Rd. as case (Institute of Transportation 24), the collision diagra and the stop line coordinate A and B are shown in Fig. 6. Fro the collision diagra, it shows that the accident risk between straight traffic flow and right turning traffic flow at south and west bound is very significantly high at the intersection, because the right turning vehicle will not keep right and the straight otorcycle will ride on the right side of the lane.

7 Chongyang Rd. Chongyang Rd. Zhongzheng N. Rd. Zhongzheng N. Rd. Zhongzheng N. Rd. Zhongzheng N. Rd. Chongyang Rd. Chongyang Rd. Figure 6. Collision diagra and intersection coordinate of Zhongzheng N. Rd./ Chongyang Rd. A field observation of dynaics traffic flow is conducted at the intersection. Taking location A in Fig.6 as exaple, the survey results show that 6% of right-turn vehicle still don t keep on right side lane at intersection. Besides, 57.6% of straight otorcycle also rides on the right side of lane. Collision risk exists between these two traffic oveents. Taking location B in Fig. 6 as exaple, the results show that about 3.7% of right-turn vehicle still don t keep on right side lane at intersection. Besides, 89.% of straight otorcycle also rides on the right side lane. Collision risk exists between these two traffic oveents. The survey result of traffic flow are shown in Figure 7. Crossing Vehicle No. Crossing Vehicle No Location A Straight otorcycle Coordinate of Stop Line () Straight otorcycle Right-turn vehicle Location B Right-turn 2 3 vehicle Coordinate of Stop Line() Figure 7. Right-Turn traffic flow conflict analysis right-turn vehicle straight otorcycle right-turn vehicle straight otorcycle Fro analysis above, it shows that right-turn traffic oveent isn t directed to right side lane at intersection and then cause the conflict against straight otorcycle traffic oveent. Therefore, signs, arkings, and control easures need to be iproved to guide different

8 direction traffic flow to different lane location separately. 4.3 Inter-green Tie and Traffic Flow Conflict Analysis Taking the intersection of Chongsheng Rd. / Hanson E. Rd. as case (Institute of Transportation 24), the accident risk exists between south bound stopping traffic flow after end of green tie and east bound starting traffic flow at the beginning of green tie, as shown in Figure 8. Therefore, the research suggests increasing red tie and yellow tie to iprove right-angle collision according to the layout of intersection for otorcycle. Chongsheng Rd. starting bound Hanson E. Rd. ending bound Figure 8. Collision diagra of intersection Chongsheng Rd. / Hanson E. Rd. and stopping and starting traffic flow bound After the setup of a new longer inter-green tie at this intersection, by conducting a field observation of traffic flow using video afterwards, the study analyzed the traffic flow crossing stop line on green tie ending bound and green tie starting bound. The analysis result shows that crossing stop line vehicles afterwards decrease fro 4.4% to 7.% due to the longer allred tie on green starting bound afterwards, and the vehicles passing the stop line after ending of green tie are reduced, as shown in Fig. 9. The risk of right-angle collision will decrease significantly.

9 中 Before 山 漢 生 iproveent-ending 改 善 前 _ 結 束 方 向 side 中 Before 山 漢 iproveent-starting 生 改 善 前 _ 啟 動 方 向 side crossing stop 通 過 車 line 輛 ( vehicle 輛 ) No crossing 通 過 tie(s) 時 間 vehicle Motocycle 通 過 汽 車 通 過 機 車 Yellow: 黃 燈 時 間 : -6~-3s ~ -3s / 全 紅 時 間 : -3s ~ s All-red : crossing stop 通 過 line 車 輛 vehicle ( 輛 ) No % of crossing vehicle during all red tie 全 紅 時 間 通 過 車 輛 佔 分 析 時 間 之 4.4% 通 過 時 間 crossing tie(s) All-red green 全 紅 時 間 綠 燈 時 間 全 All-red 紅 時 間 : -3 ~s 綠 green: 燈 時 間 : s~ crossing stop 通 過 line 車 輛 vehicle ( 輛 ) No 中 After 山 漢 iproveent-ending 生 改 善 後 _ 結 束 方 side 向 crossing 通 過 tie(s) 時 間 vehicle Motocycle 通 過 汽 車 通 過 機 車 黃 Yellow: 燈 時 間 : -7 ~ -4s / All-red 全 紅 時 間 : : -4s -4~s ~ Figure 9. Before and after analysis of traffic conflict analysis by different inter-green tie The analysis results above show that inter-green tie rule in the national guide of traffic signal at intersections needs to be revised accordingly in order to ensure otorcycle crossing intersection safely. crossing stop 通 line 過 車 輛 vehicle ( 輛 ) No 中 After 山 漢 iproveent-starting 生 改 善 後 _ 啟 動 方 side 向 7.% of crossing vehicle during all red tie 全 紅 時 間 通 過 車 輛 佔 分 析 時 間 之 7.% crossing 通 過 時 間 tie(s) All-red green 全 紅 時 間 綠 燈 時 間 全 All-red: 紅 時 間 : - 4 ~ s 綠 green: 燈 時 間 : s~ 5. MOTORCYCLE FREQUENT COLLISION TYPE ANALYSIS Resulting fro the analysis of ajor Safety proble at intersections, we found out that there are soe ost frequently occurred collision type involved by otorcycle at intersections, which are right-turn other angle collision, sae direction sideswiped collision, left-turn other angle collision, opposite left-turn other angle collision, rear end collision and right angle collision etc. The research would discuss accident issues and safety iproveent design for otorcycle accident-prone intersections regarding these collision types. 5. Right-Turn Other Angle Collision, Sae Direction At intersection with exclusive otorcycle lane, perissive otorcycle lane, or with express/slow lane traffic divider, right-turn vehicle often don t ove to right side lane to ake right turn. The right-turn other angle collision between right-turn vehicle and straight otorcycle often occurred at such lane layout. A typical case is shown in Figure (Hsu, 23). At south bound of the intersection, exclusive otorcycle lane is installed. Because the width is not enough to set up an extra lane, the research cancels exclusive otorcycle lane 5 upstrea of the stop line at intersection and ake the curb lane as ixed lane for car and otorcycle. Then, right-turn vehicle can change to curb side lane before arriving intersection and the ake right. The conflict between straight otorcycle and right-turn vehicle could be prevented, as shown Figure.

10 Chongsheng Rd. Zhongxiao Rd. 忠 孝 路 路 山 中 Motorcycle exclusive lane 2 公 尺 英 呎 Collision status Iproveent design Figure. Collision and iproveent design of the intersection of Zhongxiao Rd. / Chongsheng Rd. in Kaohsiung city 5.2 Sideswiped Collision, Sae Direction Because traffic oveents at different direction will use the sae lane under ixed traffic with otorcycle, the right-turn car and straight otorcycles will weave to cross to each other within a lane. Therefore, sideswiped collision occurred frequently on such a lane at intersection. A case is shown is Figure (Hsu, 23). The width of ixed lane is soeties too wide. Then, the right turn vehicle will not ake right turn on the right side of lane, and it will cause conflict with the straight traffic on its right side. In such case, it needs facility to guide straight vehicle to use the left side of the lane and right-turn vehicle to use right side of lane. It needs to guide different traffic oveents by setting diverging arkings for keeping otorcycle away fro conflict. Besides, the new direction arkings are also proposed at the otorcycle waiting zone to reind otorcyclists to use the collect locations to segregate the different direction oveents. The iproveent design is shown in Figure.

11 博 愛 路 Boai st Rd. 2 2 P 2 Bus 禁 行 機 車 禁 行 機 車 2 Shiquan st Rd. B 禁 行 機 車 禁 行 機 車 2 2 Collision status 博 Figure. Collision and iproveent of the intersection of Boai st Rd. / Shiquan st 愛 Rd. in Kaohsiung city 5.3 Left-Turn Other Angle Collision, Sae Direction Iproveent design Left-turn other angle collision between direct left-turn otorcycle and straight vehicle or otorcycle often occurred at intersection with the lane layout of slow traffic lane or ixed lane. An exaple of intersection is shown in Figure 2. Resulting fro field traffic survey at this intersection, any otorcycles ake left turn fro west bound to north bound don t follow two-stage left-turn regulation for otorcycle. Considering otorcycle traffic characteristics and geoetry at intersection, the new design is proposed by reoving the slow traffic lane or ixed lane for otorcycle, and then to install otorcycle direct left-turn guiding arking instead. It would separate different directions of car and otorcycle traffic oveents, and then, the traffic conflicts will decrease. The iproveent design is shown in Figure 2. Jiuhan Rd. Collision status Iproveent design Figure 2. Collision and iproveent design of Jiuhan Rd. / Fengping 2 nd Rd. 5.4 Opposite Left-Turn Other Angle Collision

12 At the intersection lacking left-turn protected signal phase, left-turn vehicles often finish left turn after ending of green tie. Soeties, at this oent, the otorcycles on opposite lane are still on departing the intersection. The collision between left-turn vehicle and opposite straight otorcycle often occurs under such situation. An exaple of intersection is shown in Figure 3. It can be iproved by reducing central-divided-island, adding left-turn signal phase, or installing left-turn guiding line etc. Then, the conflicts between left-turn vehicle and opposite otorcycle could be prevented. An exaple of iproveent design is shown in Figure 3. Nanjing Rd. Collision status Figure 3. Collision and iproveent design of intersection of Nanjing Rd. / Cathay Rd. in Kaohsiung city 5.5 Rear End Collision and Right Angle Collision Nanjing Rd. Iproveent design When otorcycle approaching intersection, soe otorcycles or vehicles are deciding to stop, but soe vehicles in front cannot stop during inter-green tie, the rear-end collision will occur. A case of collision at intersection is shown in Figure 4. Although the yellow tie is set up to theory of yellow tie, but at such intersection, a longer yellow tie is needed to reduce the rear-end collision. On the other hand, if it lacks of enough all-red tie, otorcycle couldn t leave intersection before all-red tie ends, and right-angle collision will occur, as shown in Figure 4. Although the all-red tie is set up to theory of all-red tie, a longer all-red tie is needed to prevent the right-angle collision. Therefore, the inter-green tie is needed to odified for preventing the left-turn other angle collision.

13 Rear-end collision Right-angle collision Figure 4. collision diagra and iproveent design of intersection of Chongsheng 3 rd Rd./Shidai Rd. and Yanhai st Rd./Hanin Rd. 6. NEW DESIGN GUIDELINE FOR ENHANCING MOTORCYCLE TRAFFIC SAFETY Through a series of analysis of traffic flow dynaic, collision diagra, and traffic survey, the study proposes soe innovative design concepts for enhancing otorcycle traffic safety. The new design concepts are also proved to be able to benefit the iproveent of otorcycle traffic safety at intersection by conducting before-after traffic flow dynaic analysis and the questionnaire survey to drivers and otorcyclists. The study integrates innovative design ethods and collision statues to establish new otorcycle safety design guideline at intersection. 6. Design for Motorcycle Direct Left-Turn Currently, at the intersection on one-lane and tow-lane road it usually hasn t two stage left-turn regulation easures for otorcycle. Besides, at the intersection with two-stage left-turn regulation for otorcycle, soeties, otorcycle would violate the two-stage left-turn rule and ake direct turn left with vehicle together at soe intersections where it has two stage left-turn control easures. Both situations would cause left-turn collision. Therefore, the research considers signal tiing, lane layout, and accident data etc. Instead of two-stage left-turn regulation for otorcycle, under soe conditions as follows, the intersections will be suitable to allow the otorcycle to ake direct left-turn:. At the intersection with left-turn protection phase, direct left-turn should be considered if there is no express traffic lane (only for car)/slow traffic lane(allowed for otorcycle) divider. 2. At the intersection with no left-turn protection phase, if there is no express/slow traffic flow divider and the nuber of lane is one or two lanes, then otorcycle direct left-turn should be considered. If there is express/ slow traffic divider and the nuber of accident for direct-left turn otorcycle aount is 3 ties or ore, direct left-turn also should be

14 considered. 3. If the intersections don t coply with the above, two-stage left-turn should be considered. For the design of otorcycle direct left-turn, soe new arking and signs should be created, such as diverging arkings, diverging sign, and lane-waiting zone. 6.2 Diverging Traffic Moveent 6.2. Diverging traffic oveent arking In order to guide turning vehicles and otorcycles to use proper space for turning at intersection, the study proposes a diverging traffic oveent arking to prevent turn collision and sideswipe collision. This ethod especially could be applied at wide ixed lane. The arking design principle and sybol are shown in Figure 5.. The location of erging arking should be sited at least 8 upstrea of the stop line, is suggested. 2. The location of diverging arking (I) should be sited at least 3 upstrea of the stop line, 5 is suggested. 3. The location of diverging arking (II) should be sited before otorcycle waiting zone.

15 5~ Larger than 8 5~ Larger than 3 Larger than Diverging arking Merging arking Lane width 3.5 original design lane width<3.5 Figure 5. Diverging arking design 6..2 Diverging traffic flow sign In order to strengthen the diverge of traffic flow of different directions, the study suggests that a new sign for guiding turning oveent are sited upstrea of the stop line, as illustrated in Figure 6.

16 Motorcycle can turn-left diretly 3c Turn-right vehicles ove to right side 3c Turn-left vehicles ove to left side 3c 5c 直 接 左 轉 車 可 6c 機 2c 靠 右 右 轉 行 車 駛 輛 8c 2c 靠 左 左 轉 行 車 駛 輛 8c Figure 6. Diverging sign for direct left turn and right turn oveent 6.3 Uninstall Slow Traffic Lane, Changed to be Mixed Lane At the intersection with exclusive otorcycle lane or perissive otorcycle lane, the conflict between otorcycle on otorcycle lane and other otorized vehicles on ixed traffic lane would occur frequently. For iproving this situation, otorcycle lane or slow traffic lane should be reoved on at least 6 upstrea of intersection and to install a ixed lane for otorized vehicles instead. It will reduce the traffic conflicts between different driving direction vehicles, as shown in Figure 7. Before iproveent After iproveent 機 慢 車 優 先 Figure 7. The iproveent ethod to reove slow lane or otorcycle lane 6.3 Lane-Waiting Zone for Motorcycle Perissive otorcycle lane The concept of lane-waiting zone is an iproveent of conventional waiting zone. It is to draw otorcycle waiting zone for each lane, and in the waiting zone to draw direction arrow. It is to separate different vehicles such as car and otorcycle, but also diverge different directions of traffic flow such as straight, left-turn, and right-turn oveent effectively. Under such layout, otorcycle and other otor vehicles can ove to proper location by guiding sign and diverging traffic arkings on ixed traffic lane. Besides, otorcycle riders can ove to proper location

17 for turning following the arking at lane-waiting zone. It is able to decrease the probability of turning collision and sideswiped collision. Considering left-turn regulation type and lane layout, the study proposes the lane waiting zone design guideline as follows:. At the intersection, with various directions of otorcycle stopping in a otorcycle waiting zone, both the turn arking and straight arkings should be drawn within otorcycle waiting zone. 2. At the intersection, on the lane without left-turn otorcycle, the straight arking should be installed in otorcycle waiting zone if the nuber of lane is 3 or ore. 3. At the intersection with otorcycle direct left-turn and the nuber of lanes is 2 or less, in such case, usually, one lane for left-turn and straight traffic; another lane for right-turn and straight traffic. The left-turn arking should be drawn at the left corner of waiting zone at left side lane and the right-turn arking should be drawn at the right corner of waiting zone on the right side lane for diverging the otorcycle oveents. Cobing with the lane-waiting zone, the lane arking will be designed by taking lane layout, lane width, and flow direction of lane into consideration. Its design guidelines are proposed as follows:. If the slow traffic lane or otorcycle exclusive lane exists, the slow traffic lane should be reoved fro at least 5 upstrea of the stop line and changed to be ixed lane for otorized vehicles. Besides, diverging arkings are applied to guide the traffic flow. 2. An arrow arkings would be used to guide otorcycle forward to otorcycle lanewaiting zone, as shown Figure8. 3. Motorcycle lane-waiting zone sybol, arrow arkings at otorcycle waiting zone, and diverging arking on lane should be considered with design together respectively. Figure 8. Motorcycle lane waiting zone

18 6.4 Inter-green Tie Iproveent Design The inter-green tie is highly related to rear end collision and right angle collision at intersections under consideration of otorcycle driving behaviors. Different road types need different design ethods, as follows:. Intersection on the road without express traffic lane (car only)/slow traffic lane (ixed traffic with otorcycle) divider According to the definition of Inter-Green tie, it consists of yellow tie and all-red tie. On the street without divider between the express traffic lane for car only and slow traffic lane for ixed traffic with otorcycles, called central divided street, a oveent crossing an intersection will pass through car oveent, which is ostly in the iddle of street and otorcycle oveent on the right hand side. The all-rad tie should be long enough for the car and/or otorcycle to pass through these two oveent. The tie need has to take the acceleration characteristic and speed liit both of car and otorcycle into consideration. 2. Intersection on the street with express/slow traffic divider On the street with divider between express traffic for car only and slow traffic for ixed traffic with otorcycle, called express/slow divided road in Taiwan, speed liit of express lane is usually6kph, and the speed liit of slow traffic lane is usually 4kph. Therefore, the study suggested that inter-green tie should apply express lane speed liit 6kph for calculating the yellow tie and the slow traffic lane speed liit 4kph for the all-red tie to provide safer design. 7. CONCLUSION AND RECOMMENDATION This paper investigated the collision status of ixed traffic flow with high otorcycle traffic volue, and found out the accident causes by accident diagnosis based on collision diagra analysis. Finally, the study proposed traffic safety engineering iproveent countereasures for enhancing the safety of otorcycle traffic. Through a series of the innovative design countereasures for concept of otorcycle direct left-turn design and lane-waiting zone design, the otorcycle traffic safety could be enhanced. The study proposed that the otorcycle safety design guideline. It can be taken as the practical design basis for road design for enhancing otorcycle traffic safety.

19 APPENDIX Result 肇 事 後 of 果 accident N N N,n 當 Party 事 者 of 區 accident 分 BUS,WB M(2) B(5) P(37) 有 財 A3 物 accident 損 失 車 禍 A2 有 accident(no. 受 傷 車 禍 ( 受 of 傷 injured) 數 ) A 有 accident(no. 死 亡 車 禍 ( 死 of 亡 death) 數 ) Accident 有 死 亡 with 及 injured 受 傷 車 and 禍 death 小 汽 Vehicle 車 大 Heavy 型 車 ( vehicle 公 車 貨 車 ) Motorcycle 機 車 ( 年 齡 )(age) 腳 Bicycle 踏 車 ( 年 (age) 齡 ) 行 Pedestrian 人 ( 年 齡 )(age) 駕 Driver s 駛 行 動 狀 status 態 Ret ROA Back 車 輛 倒 車 Brakes 車 輛 煞 車 Speeding 車 輛 超 速 Out 打 滑 of 失 control 控 車 輛 Stop 駐 停 vehicle 車 輛 Teporarily 臨 時 停 靠 車 stop 輛 vehicle Under 停 讓 control 管 制 停 stop 等 車 vehicle 輛 rotate 迴 轉 行 駛 Violating 違 反 交 通 driving 管 制 行 駛 道 Road 路 路 condition 況 路 面 Dry 乾 燥 road 行 駛 路 面 Moist 潮 濕 road 行 駛 光 Light 線 情 condition 形 白 天 daytie 行 駛 夜 晚 行 night 駛 Head on accident 對 撞 肇 事 型 態 Rear end accident 追 撞 肇 事 型 態 交 叉 撞 肇 事 型 態 特 殊 Special 資 料 Data Figure 9. Collision diagra basic sybol g Alcohol 酒 後 駕 駛 (g/l) ( 毫 克 / 公 升 ) signal 號 out 誌 無 of 運 operation 作 下 行 駛 有 Stop 停 讓 and 車 give 輛 way Not 未 停 stop 讓 車 or 輛 not give way Barrier 路 上 on 或 路 road 邊 物 or roadside 直 行 Head 對 撞 on Head 左 轉 on, 對 left-turning 撞 直 行 Rear 追 撞 end Rear end, right-turn 右 轉 追 vehicle 撞 Rear 停 等 end, 追 parked 撞 vehicle Right angle accident Rear end, backing 倒 車 撞 vehicle Rear 左 轉 end, 追 撞 left-turn vehicle 臨 Rear 停 追 end, 撞 stopping vechile Right 右 側 交 side 叉 撞 right Left 左 側 side 交 叉 right 撞 angle angle 擦 Sideswiped 撞 肇 事 型 態 accident Opposite 對 向 擦 sideswiped 撞 Straight 同 向 直 sideswiped 行 擦 撞 Right-turn 同 向 右 sideswiped 轉 擦 撞 側 撞 Turn 肇 事 accident 型 態 Right-turn erging 右 轉 匯 入 側 撞 vehicle 右 Right-turn 轉 側 撞 other angle, sae direction Left-turn other angle, 左 opposite 轉 穿 越 direction 側 撞 Left-turn 同 向 左 sideswiped 轉 擦 撞 Left-turn 左 轉 匯 erging 入 側 撞 vehicle Left-turn 左 轉 側 other 撞 angle, sae direction Out of control accident 失 控 肇 事 型 態 失 Out 控 肇 of 事 control Figure 2. Collision type sybol

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