Speed Limit… less?

Speed Limit… less?

Speed limits are known to reduce speed. In turn, this leads to safer roads because slower speeds mean that drivers have more time to react to developing hazards, or the impact will be less severe if a road incident occurs due to a lower velocity of force. Speed limits exist as a positive measure.
Common sense, right?

Reversing the logic, abolishing speed limits would surely be expected to make roads more dangerous. In recent times then, it seems perplexing that the notion of abolishing speed limits on UK motorways are being proposed. The seeds of this idea germinated within the issues observed related to smart motorways, for which the Prime Minister, Liz Truss, says smart motorways are “an experiment that hasn’t worked”.

If you are a driver, you will have likely seen what smart motorways are: adaptive speed limits shown on electronic displays related to traffic conditions. However, you might not have known that there are in fact three types of smart motorways:

  1. All Lane Running (ALR): no hard shoulder.
  2. Dynamic Hard Shoulder (DHS): hard shoulder is opened in busier periods.
  3. Controlled: a permanent hard shoulder with traffic controlled via variable speed limits.

When considering serious injury or deaths per billion miles travelled, there is evidence to suggest that ALR (0.19) and DHS (0.17) smart motorways are more dangerous than standard motorways (0.09). In contrast, controlled smart motorways are safer (0.06), suggesting that the danger to driver safety comes from the lack of hard shoulder rather than adaptive speeds [1].

The focus of adaptive speed limits as the cause of increased road incidents is somewhat flawed as a result. Beyond that, to suggest that we should eradicate speed limits based on the flawed reasoning that adaptive speed limits are detrimental to driver safety is simply illogical. In one respect, bold action can sometimes lead to bold results, so it is great that radical ideas are being suggested. But radical ideas need to be based in sense. Using the failings of smart motorways as a reason for this radical idea is nonsensical.

So, is there any semblance of logic to this suggestion, discounting the reason that is being used?

There is one country that has motorways without mandatory speed limits: Germany. Comparing how safe their roads are to ours could provide policy guidance. Beginning in 1935, the German autobahn came into being. These are translated as federal controlled-access highways, equivalent to British motorways. Whilst some autobahns have speed limits imposed on them, most have an unrestricted (with an advisory) speed limit.

Generally, for every billion km driven, Germany (4.2) has more dangerous roads than the UK (3.8) [2]. These figures are not specifically about motorways/autobahns though. When exploring that dichotomy in particular, the risk of death whilst using the German autobahns is about twice as high as on UK motorways, with autobahns that had mandatory speed limit showing a 25% higher death rate compared to other autobahns [3].

Eradicating speed limits doesn’t seem a sensible idea when considering such damning statistics. Hopefully, this policy suggestion is not taken forward. Whilst we currently have safe roads and attempting to make the roads even safer to meet the Vision Zero goal of achieving zero road incidents by 2050 by the revised policy is welcome, we must let evidence inform the policy recommendations. If not, our roads will become far more dangerous.