Conventional traffic management

Terminology

“Traffic management includes all physical measures designed to influence the movement of traffic on an existing network” (Thomson, 1968). Traffic management seeks to facilitate efficient and safe traffic flow by modifying the way in which the available road space is used.  In doing so it can place restrictions on traffic movement. The objective therefore is to design a traffic management plan that balances the increased efficiency and safety of some movements with the delay to others arising as a result of the restrictions.

These restrictions fall into the following four categories following the classification of Thomson (1968):

1. route restrictions; (e.g. one way systems)
2. right of way restrictions (e.g. priority regulations or signals) including junction redesign
3. parking restrictions (which may include stopping/waiting restrictions)
4. speed limits.

The last of these is considered under accident remedial measures. Traffic management can also be applied to achieve other objectives, which are covered elsewhere, including:

• environmental enhancement
• demand management
• parking management

Some specialised applications of traffic management are covered elsewhere, but are designed to satisfy the first principles set out below:

• urban traffic control systems
• intelligent transport systems
• variable message signs 

For all of these measures, enforcement may be an issue when restrictions are imposed. For example, a ban on a right turn might be easily ignored by drivers and therefore it is also crucial to consider the issue of enforcement in a traffic management plan unless the measures are self enforcing.

This note is concerned with permanent forms of traffic management and does not focus on “temporary traffic management” e.g. measures which may be used when construction or road works are in progress.

Technology

There is an entire spectrum of technology that can be employed for the purposes of traffic management. The most basic form of traffic management technology is signing; regulatory signs are enforced by traffic laws (e.g. one way street signs or signs banning turns). Traffic management can also involve the placing of bollards to prevent vehicular access (in the case of pedestrian zones). These bollards can be raised and lowered to enable certain exempt vehicles to enter the area as appropriate. At the more advanced end, electronic matrix displays may be used to direct traffic e.g. to parking places which allow dynamic display of availability of parking places. Other forms of technology can be used to implement advanced signal control. Enforcement of traffic management measures can rely on labour intensive checking or use technology such as automatic number plate recognition cameras.