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Passenger-kilometres: is the sum of the distances traveled by individual passengers (the driver being considered as one of the passengers). For example, for a vehicle with three passengers (the driver being one of them) that is driven on a distance of 10 kilometres, the number of passenger-kilometres will be 30. Light vehicles (see the Vehicle type definition below) National Research Council Canada Centre for Surface Transportation Technology 48 CSTT-HVC-TR-158 report the number of passengers for each trip (see the Trip definition below). The number of passengers in heavy vehicles with gross vehicle weight of 4.5 tonnes or more (see the Vehicle type definition below) is calculated as the average of the number of passengers at the beginning of each trip and the number of passengers at the end of each trip (see the Trip definition below).
Fuel consumed: is the amount of fuel used to operate vehicles. This variable is derived for each vehicle using the reported fuel purchases and distance driven.
The number of vehicles on the registration lists: is the average number of the registered vehicles in the registration lists at the beginning and at the end of the reference period.
The number of vehicles in scope: is an estimate of the average number of vehicles registered during the quarter based on the lists from jurisdictions and the survey responses. This number slightly differs from the previous one because we incorporate into it all our findings from the survey. Note that this number includes vehicles used and not used on the roads during the reference period.
Quality indicator: To assist the user in evaluating the potential effect of nonresponse, imputation and sampling error, an all-embracing quality indicator accompanies every estimate.
The quality indicator is a function of the CV, which takes into account the variability due to sampling and the variability due to non-response and imputation.
The quality of counts (direct from registration lists) not accompanied by a quality symbol is good or better.
Table 21: Estimates of number of vehicles in scope for Canada by vehicle body type Source: Table 3-3, CVS 2007
Table 22: Estimates of vehicle-km by vehicle class, type of fuel and body type Source: Table 7-1, CVS 2007 Table 23: Estimates of fuel consumed by vehicle class, type of fuel and body type Source: Table 7-2, CVS 2007 Table 24 and Figures 31 and 32 are taken from the Natural Resources Canada 2005 vehicle survey results and support the information found in the Statistics Canada data.
4.10 Cost benefit, fuel savings and CO2 emissions It is estimated that the costs to install a set of fairings on a 53 foot semi trailer would range between approximately $1,500 and $2,400. Various studies have concluded that the resultant fuel savings from the reduction in aerodynamic drag on a full size tractor trailer traveling at 100 km/h would provide a pay back period of less than two years on the capital investment [30, 31, 32]. However, these savings could only be realized using the flush mount fairings/skirts. The
rail style side guards provide no aerodynamic benefits, and in some situations, could actually increase fuel consumption due to air buffeting and increased drag and weight.
Using the Statistics Canada data, shown in Section 4.9, the following calculations have been
In 2005, 232,489 tractor trailer combinations consumed 7,222 million litres to drive 20,957 million kilometers. This equates to an average annual distance of 90,141 km per tractor and an average annual fuel consumption rate (diesel) of 34.5 l/100 km.
Using these figures, a typical tractor and van semi trailer that travels 100,000 km/year will consume 34,500 litres without any type of side guards. If the addition of a flush side guard provides a 5% decrease in fuel consumption as a result of lowered drag, the same combination would burn 32,775 litres, for a total savings of 1,725 litres, or $1,725 using a price of $1 per litre of diesel. Therefore, it is likely that operators would achieve pay back periods of between one and two years for each trailer that receives flush side guards. This payback period will vary depending on the number of kilometers driven and the price of fuel.
Table 25 illustrates an example of the potential fuel and GHG emission savings for a tractor trailer combination traveling at divided highway speeds of 100 km/h equipped with flush mount side guards.
Although the calculations depend on some assumptions relating to the fleet at large, it is estimated that the addition of flush mount side guards to all trailers being pulled by class 8 tractors could potentially reduce the amount of fuel being consumed by as much as 401 million liters ($401 million) annually if a modest overall gain in aerodynamics of 5% is achieved. The CO2 emissions would be reduced by an estimated 1.1 million tonnes. The reduction in fuel consumption would be 561 million litres and the amount of CO2 would be reduced by 1.5 million tones with a 7% reduction in aerodynamic drag, which is consistent with the TU Delft study .
It is assumed that there would be virtually no fuel savings and CO2 reduction with inner city straight trucks since they generally do not achieve speeds that would cause aerodynamic drag to be an issue. In fact, any small decrease in fuel consumption due to aerodynamics would be offset by the increase in fuel consumption caused by carrying the extra tare weight of the devices.
4.11 Fleet replacement and exceptions If side guards are to be mandated for Canadian trailers and trucks it will be essential to determine an installation and replacement strategy in order to understand what percentage of the fleet will be equipped and how many years will pass before the vast majority of vehicles are properly equipped. Federal regulations of this nature apply to new vehicles only and do not apply to existing equipment. This allows operators time to budget and plan for the new equipment as it becomes available. No two operators use their equipment identically, nor for the exact amount of time before retirement. However, different types of trailers typically remain in service for different lengths of time with mainline carriers. Table 26 illustrates the typical lifespan for various types of trailers used by mainstream carriers. Smaller family run businesses typically use their equipment differently and quite often for much longer periods of time due to a lack of capital. Additionally, mainline carriers will very often sell their older equipment to smaller firms thus extending the useful life of the trailers and trucks.
The report A Further Assessment of the Effect of Automatic Slack Adjusters on Brake Adjustment  shows the percentage of vehicles by model year based on the annual brake inspection blitz that takes place on Ontario highways. Table 27 illustrates the percentage of vehicles by age category for straight trucks, tractors and trailers. As an example: 72.6% of straight trucks were less than 10 years old, whereas 89.3% of tractors were less than 10 years old.
As a result, it is reasonable to assume that if side guards were mandated on new vehicles manufactured in 2010, more than 85% of all qualifying heavy vehicles in Canada would be fully equipped by 2025; however, it could be 2035 before all of the heavy vehicles (new and retrofitted on older vehicles) in Canada were equipped with side guards.
Additionally, there are some types of vehicles that simply cannot perform their duties with a side guard/fairing in place. Snow plows with side wings, street sweepers, paving trucks and some tanker trucks/trailers must have clear underside access, on at least one side of the vehicle, in order to perform their duties. For these types of trucks/trailers it would be necessary to provide National Research Council Canada Centre for Surface Transportation Technology CSTT-HVC-TR-158 an exemption such that the side guard could be temporarily removed or stowed while the vehicle is performing its intended duties and the guard must be returned to its active position when the vehicle is ferrying between jobs. The TRL study  concluded that an additional two lives could be saved every year in the UK if vehicle exemptions were removed.
The combination of replacement time and exemptions will certainly mean that many vehicles will not be equipped with side guards in the near future and possibly some vehicles, such as snow plows, that are considered high risk for under-ride, may never be equipped with side guards while performing their duties in close proximity to VRUs.
4.12 Other safety considerations
Most regulations pertaining to side guards stipulate that the guard must be fitted ahead of the rear axle group but not so far towards the front of the trailer to interfere with the articulation angle that the trailer makes with the tractor while turning. Although some guards do extend aft of the rear axle group, this is typically for aerodynamic purposes and not part of any safety regulation. Consider a full trailer that is being towed by a straight truck. The truck would have side guards ahead of the rear axle and the trailer would have side guards ahead of its rear axle.
However, a gap would exist between the truck s rear axles and the leading edge of the trailer s axles as seen in Figure 33. If a VRU were to strike that area of the combination vehicle there would be no protection and that person could certainly make contact with the front axle of the trailer. There is no practical way to avoid this situation since trailers are sometimes towed by straight trucks with converter dollies and sometimes by tractors and the front section of any trailer must remain clear for the articulation angle.
Figure 33: Example of gap in combination vehicles Since bicycles and pedestrians are not permitted to travel along divided highways, there is lower risk of an incident involving a heavy truck and a VRU. Although tractor and trailer combination vehicles spend the vast majority of their time driving on divided highways, they do enter urban areas to deliver and pickup goods. Therefore, the addition of side guards that are principally intended to save lives may rarely, if ever, come into contact with the VRUs they are intended to protect for the vast majority of the vehicle s intended duty cycle. It would therefore be more
sensible to fit highway trailers and trucks with guards that are principally intended to reduce drag on highway operations but could also provide the same impact strength as guards used in Europe and Japan when required in higher risk VRU collision areas.
The installation of side guards will not completely eliminate serious injury or death to pedestrians who come into contact with heavy vehicles. City buses typically have skirting and inherent side guards that are as low as 10 inches from the ground, which is lower than most guards found on highway transport. Yet despite these lowered guards, NRC-CSTT s literature review uncovered several incidents (the UK, Canada and the Netherlands to name a few) where passengers who were standing beside or exiting buses slipped under the chassis of the bus and were killed a result of being dragged by the bus while being pinned under the wheels.
National Research Council Canada Centre for Surface Transportation Technology CSTT-HVC-TR-158
5 CONCLUSIONSBased on data from the EU, the number of deaths and serious injuries for VRUs when involved in an incident with heavy vehicles has been reduced since the introduction of side guards.
However, it is not clear if this reduction is entirely related to side guards or if side guards are but one of the contributing factors.
The statistical data from the EU revealed there was a greater reduction in severe injuries and death for bicyclists than for pedestrians during the reporting period.
The effectiveness of the sideguards on heavy vehicles has been demonstrated by a UK study, which showed significant reductions in the number of bicyclist fatalities from before the sideguards were introduced to after the sideguards were introduced.
In Canadian urban collisions involving heavy vehicles, bicyclists and pedestrians, the front of the heavy vehicle (front, right front and left front) was the initial point of impact in 42.9% of the cases for bicyclist fatalities and 45.8% of the cases for pedestrian fatalities. The right side of the heavy vehicle (right middle, right rear and entire right side) was the initial point of impact in approximately 28.5% of cases for bicyclist fatalities and 6.3% of cases for pedestrian fatalities.
In the US heavy truck-VRU collisions, the front of the vehicle was the initial point of impact in 48.5% of the cases for bicyclist fatalities and 71.6% of the cases for pedestrian fatalities. The right side of the vehicle was the initial point of impact in approximately 22.5% of cases for bicyclist fatalities and 7.9% of cases for pedestrian fatalities.
Side guards are only part of the solution to reducing severe injury caused by heavy truck and VRU collision incidents. It is not clear if side guards will reduce deaths and serious injury or if the guards will simply alter the mode of death and serious injury. For example, VRUs may strike the guards and then be ejected or diverted into another lane of traffic to suffer a serious injury as part of secondary event with another vehicle or with the road/sidewalk surface.
Side guards alone will not eliminate serious injuries. City buses have lower built-in side skirting than side guards found on most trailers yet there are still incidences of pedestrians and passengers being killed as they slip and fall under the wheels of moving city buses.
The height, strength and location of side guards affect their ability to minimize the severity of incidents. Aerodynamic properties are also affected by these factors. If a side guard regulation is adopted in Canada it should stipulate a maximum ground clearance, a minimum strength requirement and define the areas of installation on heavy vehicles above a certain gross vehicle weight rating (GVWR).