Driving at the limit – why did we settle on 70 mph?

posted in: General News

Where did the 70 mph motorway limit come from, and what are the chances of it changing?

Speed Limit Signs

For many of the people hiring our cars and vans, they’ll be leaving our depots and heading straight towards the nearest motorway. Once they get there they’ll be sticking rigidly to the 70mph limit (ahem). But where did the 70mph limit come from?

If you’d been taking your rental car or van on the motorway before 22 December 1965, you could have driven at any speed you liked. In the 1960s that may not have been very fast. Many vans of the era topped out at around 60mph, but there were exceptions. In 1964 a Cobra Coupe GT hit 185mph, when a race team put it through its pre-Le Mans paces on the M1. It’s still the fastest vehicle recorded on a UK motorway. And even if the police had been able to catch it, they could only have given it admiring glances, because 185 mph was perfectly legal.

That changed in 1965, when peacetime fatalities reached their highest ever level following a foggy autumn that led to a series of crashes for which speed was seen as a major contributor. In December a 70 mph speed limit was trialled for four months. As you can tell, it was a successful trial.

Why 70 mph?

The above may explain why you have to limit your hire car’s speed, but why 70 mph? The figure seems to have been an arbitrary but reasonable figure, based in part of the efficiency of 1960s brake systems. In the years since there have been calls for its reduction, and just as many calls for its increase. So what’s the likelihood of you being able to legally drive your rental car at 80 mph anytime soon?

Up to 80?

In 2016, Ian Taylor, director of the Alliance of British Drivers, said: “50 years after it was introduced, the 70mph speed limit has long lost the respect of the majority of drivers. The Government should increase the limit to 80mph without further delay, to bring it into line with modern safety standards and most other EU countries.”

Certainly, the brakes on even the most standard of hire vans would now comfortably outperform 1960s equivalents, and Jim O’Sullivan, CEO of Highways England recently told the RAC that “there are parts of the network that, subject to a safety analysis, could probably operate at 80 miles an hour.”

But a change in the law is unlikely. O’Sullivan believes 70mph is so well embedded in the public consciousness that messing with it would be unwise. He sees a potential change when the roads are occupied only by autonomous cars, but that’s a long, long way off.

So if you’re about to head to the motorway in your hire car, it seems that 70 mph will remain the limit for the foreseeable future.

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