"JNugent" wrote in message
Here is a link to HC105 which deals with the 2 second gap with reference to stopping distances, nothing about providing a gap for an overtaking vehicle large enough gap for an overtaking vehicle to pull into was in the 1978 version of the HC, but not in the 1993 edition or later. The 1978 version did say that a 2 second gap would provide this space.
However, a 2 second gap does not allow sufficient space for an overtaking vehicle to move safely in front of the van in this case, which can be shown mathematically. We must make a few buttumptions first; the SC road was a NSL60 and the queue was travelling at 50 mph ( 10 mph less than the limit according to the OP), the van was maintaining exactly a 2 second gap, the OP's car is of average length of about 14 feet and he joined exactly in the centre of the gap between the van and lead car.
The 2 second gap at 50 mph is 146 feet. The thinking distance according to the HC is 50 feet (0.7 sec reaction time). By moving into the centre of the gap between the van and lead car, the gap in front of the van had reduced from 146 ft to 66ft. Which allows only 16 ft more than the thinking distance, which the van driver may well have considered to be unsafe.
If the van was travelling slightly closer to the lead car than a 2 second gap, or if his brakes were not able to slow the van as well as a car due to the load he was carrying, this would add to the concern of the van driver. However, he should have dropped back to maintain a 2 second gap from the OP, which he didn't.
Ian
