Club news: Tailgating, not brake performance, causes rear-end collisions says ADAC
Publication date: 09 November 2015
Rear-end collisions are among the most frequent types of road accidents. Tailgating is a common cause for these accidents, with the drivers often misjudging the braking performance of other vehicles. ADAC conducted a test to find out how powerful the brakes of different vehicle types are. Passenger cars came out on top in the comparison, followed by car and caravan combinations, motorcycles, light commercial vehicles and motorhomes. HGVs had the longest braking distance. A key takeaway from the study is that the critical difference in rear-end collisions emerges when vehicles do not observe the required minimum distances, i.e. when a motorcycle or an HGV tailgates a passenger car, for example.
The ADAC engineers tested two passenger cars – a VW Golf and a BMW X3. The motorcycle was a BMW 1200GS, while the car and caravan consisted of a BMW X3 and a Hymer Carado, and the motorhome was a Dethleffs Globebus T4. In the light commercial vehicle category, we used a Mercedes Sprinter, while a DAF XF represented the HGV category. All vehicles were loaded up to almost their maximum allowed capacities and had to brake to a standstill from 80kph as quickly as possible.
As expected, the car and caravan had a longer braking distance (25.2m) than the Golf (23.2m) and the BMW (23.5m). Surprisingly though, the car and caravan had a shorter braking distance than the motorcycle (25.3m). The results for the Sprinter and the motorhome were rather moderate (28m and 29.8m, respectively). Although the HGV was last in the test, its braking performance (36.2m) should not be rated as poor. After all, with a maximum gross weight of 40t, the HGV has to stop more than 11 times the mass of the other vehicles with a maximum gross weight of 3.5t. Another aspect in favour of the HGV is its mandatory standard AEBS.
The test also showed that the vehicle's load only has a minor influence on the length of the braking distance. The differences in braking performance can become critical especially when different vehicle types do not observe the required minimum distances, i.e. when a motorcycle or an HGV tailgates a passenger car, for example. Therefore, ADAC takes the view that forward alert and collision warning systems as well as advanced emergency braking systems (AEBS) should be standard, not only in HGVs.