15-Passenger Vans
Fifteen-passenger vans are popular modes of transport for various people including: community groups, schools, universities and tour operators. Since these vans became available in the 1970’s, there have been a number of collisions involving rollovers and fatalities. In a three-month period in 2000, there were four rollovers involving university sport teams and this probably stimulated the analysis by the US National Highway Traffic Safety Administration (NHTSA).
While driving 15-passenger vans is not always inherently dangerous, there are some situations that can result in erratic vehicle response that an inexperienced driver might not be able to control and which could result in a collision or rollover. Because of this, the University of Alberta requires drivers of these vehicles to have more driving experience and have demonstrated the medical fitness and the higher degree of driving knowledge and ability associated with having a Class 4 operator’s permit. In addition, drivers will attend a training session that discusses the conditions that can result in loss of vehicle control and also, demonstrate some competency in driving a 15-passenger van.
Concerns for passenger safety arose from an analysis of the accident history of these vehicles over the period from 1994-1997 and which was presented by the NHTSA in April 2001 in a report called The Rollover Propensity of Fifteen-Passenger Vans. A consumer advisory accompanied this document and described the increased chance of rollover with a fully loaded van. A second consumer advisory was issued on April 15, 2002. Such advisories have been characterized as being “unprecedented” for the NHTSA and likely reflect their perception of the urgent nature of the rollover problem.
Some factors that contribute to rollovers include: heavy loads, road and weather conditions, tire failure, excessive speed, consumption of alcohol, driver inattention and driver over-steering during an emergency manoeuvre. Many of the factors reside with the driver including: a lack of knowledge about effects of load on van driving response and inexperience in controlling this type of vehicle in different situations. This is why the University of Alberta requires drivers to have specific training to handle these vehicles. Common sense is not enough.
The Problem:
Basically because of their design, and relative to passenger automobiles, these vehicles are:
- more prone to loss of control when the vehicles are heavily loaded,
- more difficult to recover after they go out of control, and
- more prone to rollover after a driver has lost control.
Table 1 in the NHTSA report shows the incidents of single vehicle accidents and the number of rollovers for vans containing different numbers of passengers. The data showed that when the vans contained fewer than 9 persons, rollovers occurred in 12.7% of the crashes but for vans with over 10 people, rollovers occurred in 35.4% of the crashes. Only single vehicle collisions were considered because of the complexities involved in deciding why a rollover occurred in collisions involving more than one vehicle.
Number of Crashes, Rollovers and Rollover Ratios by Occupancy level ofFifteen-Passenger Vans in Single Vehicle crashes
|
Occupancy Level |
All Single Vehicle Crashes (n) |
All Rollovers (n) |
Rollover Ratio
|
Combined Ratios
|
|
< 5 |
1815 |
224 |
12.3 |
12.7 |
|
5 to 9 |
77 |
16 |
20.8 | |
|
10 to 15 |
55 |
16 |
29.1 |
35.4 |
|
> 15 |
10 |
7 |
70.0 |
The reason for the increases frequency of rollovers when the vans are heavily loaded is because the centre of gravity for the vehicle is raised as more weight is added and the higher the centre of gravity, the less force is required to cause the van to rollover (the effect of base width and raising the center of gravity on tipping can be appreciated if you consider how hard it is to topple a brick that is laid on its side versus one that is stood on end). In addition, as load is increased, the proportion of weight on the rear axle increases and this makes the vehicle more difficult to control. Computer simulations during turns in lightly loaded versus fully-loaded vans at different speeds show that the steering characteristics change depending on van load and this was rated as “ a topic for concern”. The problem associated with a high center of gravity and rollovers has also been experienced among users of light trucks and sport utility vehicles and since 2001, there have been stability rankings posted for various vehicles. A Static Stability Factor (SSF) below 1.20 is associated with increased risk of rollover and the vehicles with values around 1.0 are of particular concern. Note: these are the values before passenger loads are added to the vehicle.
Other tidbits of information:
- most fatal rollover crashes are single vehicle crashes
- rollover crashes are more likely to result in fatalities than other types of crashes
- just below half of single vehicle rollovers were reported to be preceded by an attempt to avoid the crash by a steering manoeuver. This is compared to one third for rollovers in multiple vehicle crashes.
- US Federal laws prohibit the sale of 15 passenger vans for school-related transport of students aged high school or younger. This does not apply to college students.
- most other provinces in Canada require a Class 4 licence to drive a 15-passenger van.
- on September 02, 2002, Ford Motor Company issued a warning that drivers of full-sized 15-passenger vans should be experienced and have special training to reduce the risk of rollovers.
Links to other reading on rollovers:
| Title: | Source: | Comment: | |
|
News Report: | |||
|
1 |
19 Farmworkers involved in crash (near Langley BC, July13, 2003) |
Canada.com News |
overloaded van, tire blew and van rolled. one dead, 2 serious injuries |
|
Government Reports: | |||
|
2
|
NHTSA flyer, April 2002 |
accompanied the 2nd advisory from NHTSA | |
|
3
|
Occurrence of Light-Duty Vehicle Rollovers in TRAID (1993-1997) |
Transport Canada TP14031E, March 2003 |
data from Canada |
|
4
|
US National Center for Statistics and Analysis Research and Development DOT HS 809-438 April 2002 |
lots of US data from 1991-2000 | |
|
5
|
US National Transportation Safety Board, Oct 2002 |
data from 1990-2002 and analysis; discussion of steering characteristics | |
|
6 |
J.W. Runge, M.D. administrator, NHTSA |
statement to a US Senate committee, Feb 26, 2003 | |
|
Other Websites: | |||
|
7 |
Outdoor Ed.com |
history of US transport legislation | |
|
8 |
RolloverLawyer.com |
what a great web name! many informative articles here | |
|
9 |
C. Johnson web page |
this individual has posted his opinion on a variety of subjects. I do not know if the calculations on the rollover physics are correct nor do I endorse any of the other information located here | |
|
10
|
Travelling down the Safer Road Alternatives to Dangerous 15-passenger vans |
Church and Worship Technology, June 2002 |
This publication name is runner up to the RolloverLawyer.com name |
|
11 |
Safetyforum.com |
some history of accidents and US legislation | |
|
12 |
School Transportation News |
links to many reports on 15-passenger vans | |
|
13
|
Rollover Hazards Associated with Operational Safety Problems of 15 passenger vans |
L. C. Moore, Registered professional engineer, Dec 02, 2002 |
letter to the Brotherhood Mutual Insurance Co. |
|
Some University Policies: | |||
|
14 |
University of Washington policy, April 2003 |
also applies to vans rented from outside the university motor pool | |
|
15 |
New requirements for use of 15-passenger vans and the
|
University of Maryland, Oct 15, 2002 |
policy and requirement for on-line and hands on training for driving 15-passenger vans |
orig: July 18, 2003 BGMcC