10 ways that 20mph limits benefit drivers

Far from being anti-motorist, 20 mph limits give drivers many advantages. That’s why 72% of drivers believe 20’s Plenty on residential streets[1].

[1] National Centre for Social Research, British Social Attitudes: the 22nd Report, 2005


Drivers will save money, be healthier and greener when authorities adopt community-wide default 20 mph limits without humps.  Some roads will have higher speeds where merited.  Average trips take less than 40 seconds extra. Driver benefits include:-

1 Fewer injured car users.  Overall there were 22% fewer casualties in Portsmouth: drivers had 23% fewer and passengers 31% fewer after 2 years of wide area 20 mph limits[1].  Elderly drivers had 50% fewer injuries and 40% fewer injured passengers.

2 Fuel use, CO2 and costs fall 12%[2]. German 30km/h (18.6 mph) zones led to car drivers changing gear 12% less often, braking 14% less often and using 12% less fuel.

3 Less Congestion. At 20 mph more cars occupy the same road space due shorter gaps between them relative to 30 mph, easing traffic ‘flow’. Junctions are more efficient as drivers can merge into shorter gaps.  Less risk encourages sustainable travel and public transport.

4 Easier parking. Fewer unnecessary car trips frees up road space and parking. 

5 Cleaner air quality especially benefits motorists. They breathe in-car air which is three times more polluted than at the pavement[3].  Standing traffic, which produces unnecessary fumes, reduces as traffic flow becomes smoother. Less fuel is burnt due to less acceleration and the transfer of some trips away from cars towards walking, cycling and public transport.

6 Motoring costs drop.  As crashes fall in severity and frequency, so do legal and repair bills. This will be reflected in motor insurance premiums dropping in 20 mph limit post codes.

7 Repair bills fall. Vehicles maintain value from fewer crashes, less brake and tyre wear.

8 Stress reduces as drivers have more time to see and react to hazards. Fewer road rage incidents occur due to more considerate driving styles, including less dangerous overtaking and it is easier to pull out. With casualties down by 22% some drivers will suffer less emotional trauma and anxiety from their part in liability for crashes. Noise also reduces.

9 Less parents’ taxi duty. Road danger reduction brings safer independent child travel, improves their life skills, and frees up parents for more productive activities than driving.

10 Society benefits. Fewer road victims frees up facilities for other health needs. Fewer work days are lost. Widow, disability benefit and care savings. Active travel cuts obesity and heart disease.  Inequalities reduce as less children die. Quality of life rises. Fewer potholes.


Total 20 involves signage and is implemented without speed bumps. It’s a vote winner. It’s hard to find anyone living in a 20 mph limit who wants it back at 30 mph!

[1] DfT. Interim Evaluation of the Implementation of 20 mph Speed Limits in Portsmouth Final Report - Sep 2010

[2] An illustrated guide to traffic calming. by Dr Carmen Hass-Klau (1990)

[3] Environmental Transport Association. Road User Exposure To Air Pollution Nov 1997

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