SPIs on Vehicles

Introduction

National vehicle fleet's crashworthiness and compatibility are suggested as SPIs on vehicles. Monitoring of the fleet, in terms of its composition and age, can assist countries in designing policies to ensure that road users are not placed at unnecessary risk of injury as a result of poor vehicles or an unfavourable fleet mix. The minimum information which is required to produce some calculations of vehicle age (as a proxy for vehicle crashworthiness) and fleet composition (as a measure of compatibility), are total number of vehicles listed by:

• Year of manufacture (or year of first registration)
• Vehicle type (using definitions compatible with CARE)

Read more about SPIs for passive vehicle systems in the report Safety Performance Indicators: Theory

Measurement method

For those countries that are able to provide it, listing passenger cars by make, model and year of manufacture also enables calculation of the EuroNCAP score of vehicles manufactured after 1994. EuroNCAP is widely used as an indicator of passive safety for individual vehicles to give consumers a guide to the crashworthiness of specific makes and models. However there is no current recognised measure of an entire vehicle fleet. For passive vehicle safety SafetyNet researchers collected 2003-data containing the entire vehicle fleet database according to vehicle type, make, model and year of first registration. EuroNCAP scores are only currently available for passenger cars, so the SafetyNet analysis concentrated on those vehicles within the national fleet. For the SafetyNet study, it was decided that a EuroNCAP score, although describing a specific model variant, would be applied to any vehicle of the same model, to ensure a larger sample size. For each country, a EuroNCAP score was attributed to eligible vehicles. An average figure was then calculated for each year and weighted by the number of vehicles present in the 2003 fleet from that year. An overall average EuroNCAP score was then awarded for each country and together, with the median age of passenger cars in the fleet, these two figures made up the SPI for each country.

In order to validate the SPI with real-world data, car occupant fatality rates in each of the countries were considered. The number of car occupant fatalities in 2003 for each country was divided by the number of passenger cars present in each 2003 fleet, to give a figure for the number of car occupant fatalities per million cars. The average EuroNCAP score for each country was weighted by the percentage of passenger cars in a country’s 2003 fleet, which were less than 10 years old. This figure for each country was then plotted against the car occupant fatality per million cars figure for each country.

The SPI Manual discusses how databases on vehicles can be further improved. In order to improve accuracy of the database and resulting SPIs, procedures should be in place to:

• Remove scrapped vehicles from the database.
• Ensure that vehicles that are not taxed and/or licensed still appear on the database if they are still being used on the roads.

Recommendations

It is recommended that vehicle fleet data is the responsibility of a national governmental body. This is one way of ensuring the accuracy of the vehicle fleet database as a record of the vehicles that are actually on a country’s roads at a point in time. Additionally, it recommended that the vehicle fleet database includes:

• Detailed and accurate descriptions of vehicle makes and models.
• Classifications of vehicles according to vehicle-types compatible with CARE definitions.
• Distinctions between smaller (less than 3.5 tonnes) and larger goods vehicles (since these have different compatibility in collisions with passenger cars or vulnerable road users).