When it comes to motorway journeys, the only thing worse than being stuck in congestion is being stuck in congestion and having no idea about the reason why. Travelling back home tonight, we had about twenty minutes on the M1 when the traffic slowed to about15-20 miles per hour. Worse still, we kept seeing signs advertising that the national speed limit was in effect but, as we got a few car lengths away, they switched to 50 and then 40 as a temporary limit. Then, after all that, the traffic suddenly started flowing again and everything cleared up.
This is one of the things that makes me very sceptical about the concept of “smart motorways”. I know that computers can’t be relied on to work reliably at all times. Crashes are bad enough when they just involve software but throw in a bunch of soft people in hard metal speed machines and it has the potential to become carnage. If the system can’t explain a visible slow down, is it really going to cope with the vehicle that breaks down and can’t safely get to one of the refuge zones?
That’s not to say that old-style motorways are perfect. They still have plenty of dangers and you still get stuck in traffic with no explanation. However, the investment in providing a continuous passive safety zone (ie. the hard shoulder) seems a much more solid idea than thinking that cameras and control software can be trusted to do the job.