How communities can get involved in the setting of speed limits

RCAs set speed limits

Responsibility for setting speed limits lies with the road controlling authority (RCA) that operates and maintains the road.

• For state highways, Transit New Zealand is responsible
• For local roads, the local authority is usually responsible.

The roles and responsibilities of RCAs are defined in Land Transport Rule: Setting of Speed Limits 2003, which came into effect in 2004.

Communities must be consulted

The Rule says that before setting a speed limit or designating or changing an urban traffic area, an RCA must consult with 'persons that may be affected by the proposed speed limit'. The groups that must be consulted are listed in the Rule. They include any local community and any organisation or road user group that the RCA considers to be affected by the proposed speed limit.

This means that communities and organisations affected by a speed limit have the opportunity to be involved in the setting of speed limits for roads in their area.

If you're concerned about a stretch of road in your area and would like to have your say, there are some important things about the setting of speed limits that you should know first.

The speed limit is not always the same as the safe speed

The speed limit that is set for a road is the maximum legal speed that a driver can travel at on the road in perfect conditions. A driver must constantly evaluate the road, traffic and weather conditions, and judge the safe speed for the stretch of road they are on. If a driver is not driving to the conditions, then they are driving too fast, even if they are within the speed limit.

The safe speed for a road is not a fixed value. It may range from the legal limit to virtually nothing – for example, in conditions of extreme ice or wind. Traffic congestion also affects the safe speed, as does the presence of pedestrians and activity from roadside areas such as shopping centres and recreation facilities.

Speed limits must make sense to drivers

It's important that speed limits are appropriate. They must be credible and make sense to road users. Unrealistic speed limits do not encourage voluntary compliance. In some situations, they may even increase the potential for crashes – for example, the expectation of some road users may not match the reality of the speed of moving traffic. Pedestrians and cyclists in particular – but also motor vehicle drivers in a 'give way' situation such as at intersections or driveways – are likely to expect traffic to be travelling at the signed speed, when in reality the actual speed may be significantly higher. Available gaps for crossing the road or pulling into the traffic stream will be shorter than they appear.

Just reducing speed limits won't prevent crashes

It's easy to think that installing a lower speed limit will automatically reduce vehicle speeds, and therefore increase safety. However, research has shown that simply reducing a speed limit will often have only a marginal impact on driver speeds. The main factors influencing a driver's choice of speed are the road environment and prevailing traffic and journey conditions.

Residents in rural lifestyle areas are often concerned about the speeds at which vehicles travel past their homes. Much of this traffic is likely to be commuters travelling to and from work. Many of these drivers will be in a hurry and will travel some distance on rural roads. Reducing the speed limit is likely to have little effect on the actual driving speeds in situations like this.

How RCAs set speed limits

The factors an RCA must consider in setting speed limits are in Land Transport Rule: Setting of Speed Limits 2003.

The Rule says that a road controlling authority must consider the safe and appropriate speed limit for a road by looking at

• the function, nature and use of the road
• its environment
• land use patterns
• whether the road is in an urban traffic area or a rural area.

Speed Limits New Zealand sets out the procedures for calculating a speed limit, and is part of the Rule. The procedures require the RCA to measure the amount of roadside development (such as houses and shops) and to evaluate the design and use of the road.

RCAs are able to set any speed limit from 10 to 100 km/h, in increments of 10 km/h. They are also able to set minimum speed limits and variable speed limits.

Last updated: 13 October 2005