Galway Cycling Campaign -Feachtas Rothaiochta na Gaillimhe

20mph As A Standard Speed Limit

Why Galway Needs It.

© Galway Cycling Campaign, April 1999

(1) Reducing fatalities

A pedestrian hit by a car at 40mph has only a 15% chance of surviving.  At 30mph this chance increases to 55%.  But at 20mph the chance of survival increases to 95%. [1] In Galway city 28% of accidents involve pedestrians, but these account for 43% of fatalities.   [2]  128 people were injured, and 6 killed in traffic accidents in Galway City in 1997. [3]

(2) Reducing casualties

Lowering the speed limit to 20mph reduces total road traffic casualty levels by around 60% and child casualties by around 70%, according to studies in both Britain and Denmark. [4] This would mean at least 80 fewer road traffic casualties in Galway City each year.

(3) Reducing costs

The National Road Authorities own method for estimating the cost of road deaths and accidents shows the following, the Galway fatalities can be estimated as having cost £4.7 million, while the injuries depending on seriousness cost anywhere from £1 million to £11 million.  These costs are being incurred at a time when there are approx.  4,000 people on surgical waiting lists alone in the Western Health Board area. [5]

(4) Reducing congestion

(a)     Congestion on urban roads is governed mainly by the capacity of junctions, and lower speeds increase that capacity.  Time savings at junctions gained through lower speeds in Växjö, Sweden, led to journey times being reduced overall; [6] where 30kph zones have been introduced in Germany, drivers spend 15% less time sitting stationary in their vehicles. [7]

NB: In Galway City traffic varies from hardly moving at rush hour to dangerously high speeds at other times.  Reducing the standard speed limit to 20mph will not increase average journey times, but will encourage a constant and more efficient traffic flow.

(b)     Traffic collisions are a major cause of congestion in Galway; lower speeds lead to far fewer crashes (see section 2, above) and thus smoother traffic flow.  An experiment in west London restricting speeds through use of speed cameras ascribed time savings to precisely this reduction in collisions. [8]

(c)     A safer environment on the roads is the key to turning more people to cycling and walking, thereby reducing the number of motor vehicles and reducing congestion.  The introduction of Brighton’s Hanover 20mph zone in summer 1995 saw a 22% reduction in motor vehicles, [9] while as a result of the ‘cycle-friendly towns’ scheme in West Germany, cycle use rose by 50% between 1981 and 1991. [10] As Galway Corporation notes in the City Development Plan 1999, "Walking and Cycling are totally sustainable mode of transport.  There is no negative impact on environmental quality and these transport modes are healthier and more efficient than private car transport."  During term the "School Run" accounts for up to a fifth of rush hour traffic in Galway. [11]  

(5) Reducing pollution

Pollutants such as nitrogen oxides and particulates have been identified as possible triggers of asthma and other health related problems.  Lower traffic speeds reduce air pollution by improving traffic flow.  "Exhaust emissions always contain larger amounts of carbon monoxide, hydrocarbons and nitrogen oxides when a vehicle is accelerating or decelerating, or when the engine is idling, than when the vehicle is cruising." [12]   In stationary traffic car occupants may be exposed to higher levels of pollutants than pedestrians or cyclists on the same streets.  

Where 30kph zones were introduced in Germany, car drivers on average had to change gear 12% less often, used their brakes 14% less often and required 12% less petrol. [13] One study of the effects of traffic calming schemes on exhaust emissions revealed reductions of 30% in nitrogen oxide, 20% in carbon monoxide and 10% in hydrocarbons. [14]

The same holds true for noise pollution, with a lower speed always resulting in a lower noise level.  Again, the major benefits may come from the smoother flow gained from lower speeds, as a large proportion of noise is generated through acceleration. [15]

(6) Who ever heard of a 20 mph speed limit?

As strange as it may seem, Ireland is one of the few countries in Northern Europe that does not have speed limits lower than 30 mph.  Many other European Cities and Towns have successfully introduced 20 mph or lower speed limits e.g.  Delft, Odense, Berlin, Dortmund. [16]   While there may be initial resistance most residents now support lower speed limits.  In the city of Graz, Austria 8 out of 10 residents now support the lower speed limits which have been implemented on three quarters of the city's road network.  York, a medieval city and university town like Galway, has already imposed 20 mph speed limits on over ten miles of city streets and is aiming to become the first traffic calmed city in the UK. [17]   Where 20mph zones have already been introduced in London they have been widely welcomed (as they have elsewhere throughout Britain); "overwhelming support" from the public led to the Kew zone’s being made permanent in December 1992.  In the UK overall there are now over two hundred 20 mph zones.   [18]

(7) Agreeing with the experts

A major study of optimal speeds in Britain Speed Control and Transport Policy, by Stephen Plowden and Mayer Hillman (1996) concluded that 20mph should indeed be the standard urban speed limit, although it argued that 15mph might be justified in university towns or where there are large numbers of tourists (both of which apply to Galway).

Adapted by the Galway Cycling Campaign from "20mph as a standard speed limit, Why London needs it" by John Hilary, London Cycling Campaign, April 1999

© Galway Cycling Campaign, April 1999

Galway Cycling Campaign can be contacted at:

c/o Galway One World Centre, the Halls, Quay St., Galway.