Hybrid and Electric Cars: Risks and solutions Jorge Leite National Director
Noise or information? Generally speaking traffic sounds are thought of as noise. However we all make use of the information transmitted by the sounds.
Noise or information? Visually impaired pedestrians can use traffic sounds to detect a junction, to walk parallel to the road, to identify the right time to cross the street and to know which street they are in. They use traffic sounds to detect the presence of vehicles and predict their movements.
Noise or information? Fully sighted pedestrians also use the lack of noise to choose the right time to cross (without looking). Cyclists may interpret a lack of noise as the right time to change lane, or as a sign they can relax because no vehicle is approaching from behind.
Noise or information? However, information only exists, or can only be interpreted, when the sound is at a comfortable level. Too high impossible to discriminate sounds Too low impossible to detect
Reduce noise polluition As a result ACAPO is in favour of reducing noise pollution in overall terms because this will improve the quantity and quality of the aural information available to visually impaired pedestrians and the general public. However each vehicle should produce sufficient sound for it to be detected and for its movements to be intepreted, which is not the case with hybrid and electric cars travelling at low speeds.
What are the risks? The most obvious risk is that the pedestrian will step into the road at the wrong time. It can happen when a car is moving or stopped.
What are the risks? The less obvious risk is that visually impaired pedestrians lose confidence and stop walking around town by themselves. They could lose their independence.
Accidents and Company Accidents, Near-accidents and, Incidents
Accidents and Company accident physical contact between the vehicle and the pedestrian near-accident physical contact does not occur by a matter of millimeters or fractions of a second. incident there was no accident because someone warned the pedestrian (sounded horn, shouted) and the pedestrian did not step in front of the vehicle or stepped back quickly.
Accident and Company The statistics report road accidents but not near-accidents and incidents. In a factory a series of incidents will lead to a new procedure. In the street a series of incidents may lead to the pedestrian losing confidence in his/her ability to cross the road.
Are we exaggerating the risks? The position of the NGO s representing visually impaired persons has been criticised explicitly in the USA and indirectly in the UK.
Are we exaggerating the risks? Nobody disputes the fact that hybrid and electric cars emit less noise at low speeds. People question whether these vehicles are involved in more accidents with pedestrians.
Are we exaggerating the risks? The NHTSA (National Highways Traffic Safety Administration) published a technical report in September 2009 entitled: Incidence of Pedestrian and Bicyclist Crashes by Hybrid Electric Passenger Vehicles
NHSTA study Aim: To analyse the incidence of accidents with hybrid and electric cars (HEV) involving pedestrians and cyclists and to compare the rates with accidents involving internal combustion engine cars (ICE) in similar conditions.
NHSTA study HEV 8 387 vehicles involved in accidents 77 accidents with pedestrians (0.9%) 54 accidents with cyclists (0.6%) ICE 559 730 vehicles involved in accidents 3 578 accidents with pedestrians (0.6%) 1 862 accidents with cyclists (0.3%)
NHSTA study According to the authors: This study found that pedestrian and bicyclist crashes involving both HEVs and ICE vehicles commonly occurred on roadways, in zones with low speed limits, during daytime and in clear weather, with higher incidence rates for HEVs when compared to ICE vehicles.
NHSTA study Beware of the numbers! The study does not say that 0.9% of HEV crash into pedestrians or cyclists, but rather that 0.9% of the accidents involving HEV also involved pedestrians or cyclists. In other words, when the driver of a HEV has an accident he/she is more likely to crash into a pedestrian or cyclist than the driver of a ICE (9 times per thousand accidents compared to 6 times per thousand).
NHSTA study There could be a number of variables: - the type of driver; - HEVs are driven in urban areas where the number of pedestrians is greater; - the almost silent engine at low speeds invites the pedestrian to crash into the vehicle.
Are we exaggerating the risks? Project report PPR525 was written at the request of the Transport Ministry by the Transport Research Laboratory and published in 2011 Assessing the perceived safety risk from quiet hybrid and electric vehicles to vision-impaired pedestrians
Project PPR525 According to the authors: HEV are involved in less accidents than ICE; Proportionally more HEV hit pedestrians than ICE; The data available do not explain the difference; The number of accidents involving pedestrians with disabilites is too small to reach a conclusion; Any rules relating to HEV vehicles should be extended to include the quieter ICE vehicles.
Are we exaggerating the risks? The authors of the US study and the UK report talk of the need for more data so as to analyse fully the variables and identify the risks. But more data requires more accidents.
Are we exaggerating the risks? No, we aren t! Because the number of accidents is irrelevant. What influences a pedestrian s behaviour is not the real risk but rather his/ her perception of the risks.
Perceived risk The study identified the key variable in the title: The perceived (subjective) risk means: If I feel safe, I ll cross the road; If i don t feel safe, I won t cross the road alone; (or possibly) If I get nervous, I ll risk it at the wrong time.
perceived risk We not only have to eliminate accidents but also reduce as far as possible the number of near-accidents and incidents. The solution already exists!
Nobody disputes the fact that hybrid and electric cars emit less noise at low speeds. Nobody disputes that it is easier to detect a hybrid or electric car fitted with an alert sound that is activated when the car travels at a low speed.
The US legislation Pedestrian Safety Enhancement Act of 2010 The law calls for an increase in pedestrian safety and requires the Transport Secretary to study and define, by January 2014, a safety standard that provides a way of alerting visually impaired and other pedestrians to motor vehicle operations.
The US legislation HEVs will have to be fitted with an alert sound that allows pedestrians to detect their presence, direction of travel, location and operation; The driver is not required to activate the sound, nor can he/she switch it off; The alert sound shall be emitted when the vehicle noise is too low to be detected by a pedestrian. The manufacturer may supply one or more sounds for each vehicle; The manufacturer must supply the same sound or set of sounds for each make and model
The alert sound Under the US legislation the alert sound must be understood by pedestrians as the sound of a vehicle in operation.
ACAPO s expectations An alert sound that is understood by pedestrians as the sound of a vehicle in operation. A sound that allows pedestrians to calculate the position, movements and speed of HEV vehicles when they are stopped or travelling at low speed. With the aim of eliminating as far as possible accidents, near-accidents and incidents, and also to retain the current levels of independence that visually impaired pedestrians enjoy.
Jorge Leite jorgeleite@acapo.pt