Advocates for lower urban speed limits are calling for wider adoption of speed-limiting technology in private vehicles, following the implementation of a 20mph speed limit policy covering over a third of Wales’s road network. Phil Jones, former chairman of the Welsh Government’s 20mph Task Force Group, proposed that drivers voluntarily equip their cars with speed limiters to act as “pace cars” and help enforce speed restrictions, even when some motorists choose to disregard them.

Jones told a House of Commons transport committee that the concept would involve fitting intelligent speed assistance (ISA) systems that use GPS data, digital maps, and front-facing cameras to monitor and regulate vehicle speeds in real time. ISA technology, which became mandatory in all new vehicles sold within the European Union from 2022, typically provides warnings to drivers when speed limits are exceeded, though current regulations allow it to be overridden or switched off at the start of each journey.

Jones emphasized that the idea of using private cars as “rolling road blocks” could complement existing public vehicle fleets already equipped or slated for ISA installation. He explained that such a collective approach would not require universal compliance to influence overall traffic flow, stating, “We don’t need every driver of every vehicle to be obeying the speed limit to influence the majority of the traffic flow.”

Transport for London’s safety director, Lilli Matson, noted plans to outfit the capital’s entire bus fleet with ISA by 2030, reflecting a broader push toward technological assistance in managing urban speeds. Meanwhile, Jones defended the Welsh government’s 20mph limit rollout amid criticism and public opposition. A petition against the policy, described by some as “disastrous,” collected nearly 470,000 signatures, but Jones argued such resistance represented a “loud minority,” with a “silent majority” in Wales supporting the limits.

Jones criticized the government’s latest Road Safety Strategy for not adopting 20mph limits as a baseline standard, arguing that success should be measured by compliance with safe speeds rather than adherence to higher limits. He questioned whether a collision at 29mph in a 30mph zone was preferable to one at 25mph in a 20mph zone, highlighting safety concerns associated with incremental speed differences.

Campaigners advocating for stricter controls suggested further technological interventions. Adrian Berendt, director of the campaign group 20’s Plenty for Us, pointed to electric bikes that automatically restrict speeds in designated “go slow” areas as a potential model for cars. Berendt noted that vehicles could be limited to significantly lower speeds in sensitive residential zones to enhance safety.

In parallel, the government advisory body Active Travel England recently recommended setting speed limits around 20mph on rural roads shared by drivers, cyclists, and pedestrians, a departure from the traditional 60mph default. This guidance aligns with broader efforts to reduce vehicle speeds and improve road safety in mixed-use environments.