Powered Two Wheelers

Summary

There are two quite different types of powered two wheelers (PWT's):

• mopeds with 50cc and restricted top speed;
• motorcycles.

Use of PTW

With two wheels in line, minimal bodywork and high power to weight ratio, PTW’s are a economical means of transport. Riding a PTW gives a special sensation which is attractive to some groups of riders. Riding a PTW is also much more dangerous than using another motor vehicle.

PTW’s are more popular in southern European countries. Greece has the highest ownership rate with 150 mopeds and 100 motorcycles per 1000 inhabitants. In most countries the number of mopeds is decreasing although at different rates or has stabilised. The number of moped fatalities follow the same trend. Many countries have a large proportion of moped fatalities among riders 25 years and older, other countries show a majority aged under 25 years. The trends for numbers of motorcycles are quite different. With the exception of middle European countries almost all countries have experienced an increase in number of motorcycles, again at various rates. The increase is stronger for older motorcycle riders. Middle European countries show an ongoing downward trend in number of motorcycles. Most countries have a large proportion of motorcycle fatalities among riders aged 25 years and older.

Safety of PTWs

The total number of PTW fatalities in 2005 in Europe (as represented in IRTAD) was 7030, which is 15% of all traffic fatalities. 50% of fatally injured moped riders were under the age of 25. 75% of the motorcycle riders killed in traffic were 25+.

PTW accident characteristics and injury mechanisms

Studies of moped and motorcycle accidents find large proportions of collisions with a car driver who should have waited for the PTW, indicating problems with the perception of PTW’s. These problems are both physical due to the small size of the PTW and psychological: the presence and behaviour of PTW’s is not expected by car drivers and sometimes not given enough attention by them. Some PTW riders contribute to the problems by speeding. A partial solution to the perceptual problems for both moped and motorcycle is the use of headlights during daytime and the wearing of fluorescent/retroflective clothing.

Contributory factors in accidents

Age and experience are the main factors related to the PTW rider. Young PTW riders have much higher accident rates than older ones, even if corrected for lack of experience. The accident rates of middle aged PTW riders are still many times higher than of car drivers of the same age. Different types of experience with a PTW (years of riding, recent or frequent riding, familiarity with a specific motorcycle and familiarity with specific condition) all contribute to a lower accident rate to some extent. Riding conditions, rider motivation and riding style contribute to accidents as well.

Mopeds with their small engine and low top speed have lower fatality rates than motorcycles, but higher accident rates when less severe injuries are included. Little is known about the accident rate of 125cc motorcycles, which is unfortunate because some countries have a low minimum age limit of 16 years for these vehicles and/or allow access with only a car license. Sports motorcycles have been found to have higher accident rates than other types of motorcycle. This is possibly the consequence of the riding style of the riders who choose this type of motorcycle, a riding style which includes speeding. Power to weight ratio is probably more related to accident rate than cubic capacity.

With only two wheels in line PTW’s are difficult to control. Poor condition of the road surface or small objects on the road are likely to cause loss of control of a PTW.

Accident prevention and injury protection

There are a number of measures that can make riding a PTW safer. These can focus on reducing the number of accidents occurring or improving injury protection when accidents do occur. However, even if these measures were used to their full potential, the accident rates of PTW’s will still be much higher than for driving a car. A further reduction in number of PTW accidents is only possible with a very restrictive licensing system with access only at higher age limits, more extensive training and testing, lower power to weight ratios or restricted top speed. These measures will not be popular with present user groups or the PTW industry. Discouraging or restricting the use of PTW’s may be more acceptable if alternatives are made more attractive. Pedal bike, public transport or cars do not seem to be alternatives to the present use of PTW’s. (Electric) power assisted pedal bikes and tilting three wheelers could become acceptable alternatives in the near future for some existing groups of PTW users.

PTW’s provide little protection against injuries in the case of an accident. Injuries to the legs are frequent, but injuries to the head are more severe even though wearing a helmet. Accident studies show head injuries would have been much more frequent if helmets had not been worn. From the point of view of preventing injuries there is no reason to exclude any group of PTW users from compulsory wearing a helmet. Wearing protective clothing would prevent many minor injuries. Collisions between the front of the PTW and the side of a car are frequent, with many riders falling before the collision as well as many riders departing from the PTW during the collision. Devices to prevent injuries in these cases, like airbags and leg protectors are still experimental. Breaking a PTW is difficult and loss of control in an emergency situation is often found in accident studies. Some of these accidents can be prevented with ABS/CBS brake systems on motorcycles but they are still too expensive to be fitted to all PTW’s. Injuries from single vehicle accidents are more severe when hitting a fixed object like a guard rail. Devices have been designed to be retrofitted to existing guard rails to prevent injuries to motorcyclists.

Licensing requirements

Given the characteristics of a PTW and their high accident rate it is obvious that riders need a high level of competency. A graduated licensing system will reduce the number of motorcycle accidents because:

• Young riders are not allowed to ride a motorcycle
• Learning and gaining experience is restricted to low risk conditions
• Licensed riders are more competent (as compared with other systems)
• Some potential riders are discouraged from obtaining a motorcycle license

The (proposed) European directive on licensing is not a graduated system in the strict sense: from age 18 riders have direct access to a 35kW motorcycle and from 24 years to an unrestricted motorcycle. The adverse effects of immaturity may be minimised with these age limits, but not with the age limit of 16 for 125cc motorcycles and 16 (or even 14) for mopeds. In terms of accident prevention a better licensing system has

• A minimum age limit as high as for a car license
• At least two stages of riding under low risk conditions on a low performance motorcycle with a combination of compulsory training and unsupervised practising
• Testing before and at the end of each stage
• No direct access to high performance motorcycles
• Moped riders start with compulsory training, followed by a period with a provisional license and ending with practical training/test
• But even an improved licensing system may not prevent higher accident rates caused by rider motivation and riding style. The effects of voluntary, advanced training programs will depend on the motivation of the participants. With riders who are safety minded these programs can be expected to improve their behaviour and prevent accidents. With performance oriented riders the result may be the opposite.

Violations

Certain types of violations by PTW riders (speeding, drinking, tampering of the engine, not wearing a helmet) contribute to accidents/injuries. Depending on the proportion of riders violating the law, increased enforcement effort may be needed.

Road design

In road design (in particular all kinds of speed inhibitors and lane markers) and in road maintenance more attention is needed to prevent PTW accidents.