Measure type: Directing traffic flows

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Directing traffic flows is the traffic management measure of reducing risk by reducing the opportunities for an offender to approach a target by specifically targeted reduction of his mobility.


Directing traffic flows is a traffic management measure of directing the traffic in a preferred way. Whereas this usually is done from a traffic management perspective to improve throughput of a road network[1], it can also be applied to increase security. In this case, the measure is usually intended to separate potential offenders from locations or circumstances where they might do harm. Examples of direction of traffic flows for security reasons include building barriers for vehicles, to provide safe transportation to and from entertainment centres across high-risk areas, to ensure a car-free zone around a building as a protection against car bombs or to separate pedestrians from motorcycles to prevent snatch theft.

A traffic flow measure can be directed at all traffic, or only certain modes. For example, a water obstacle would be effective against all road transportation, a gravel pit would stop rolling vehicles, but not pedestrians and an average fence would stop pedestrians, but not ramming vehicles.


Examples of directing traffic flow measures are:

By physical route guidance

  • Signposts
    Signpost indicating clear routes to popular destinations
  • Traffic signs
  • Route guidance with Dynamic Route Information Panels (DRIP)
  • Route guidance and traffic information provision via navigation systems

By hard and soft barriers blocking unwanted traffic flows

  • Elevation to stop rolling vehicles or discourage pedestrians
  • Water or gravel barrier
    Use of water as friendly barrier
  • Green barrier
  • Bollards
  • Traffic slowing measures, such as speed ramps, discouraging rat running
    Speed decreasing measures can decrease the appeal of shortcuts as rat-running routes.

By psychological barriers or route guidance

  • By indicating wanted pathways by lighting
  • By discouraging unwanted pathways by making them seem dead-end
  • By intentionally designing one route to be more attractive than another (for example intentionally making an alternative road look narrow and obscure for cars, or by planning popular attractions for tourists to be along a defined route)

By providing natural, direct routes

  • Designing pathways directly and obviously to main points of interest equipped with all required security features
    Basingstoke station featuring explicit, direct access routes
  • Increasing traffic flows in desired main through routes in a city by facilitating shorter travel times with green waves and thereby reducing traffic in less desired areas.

By regulation

  • One-way streets
  • Prohibited places
  • Restricted access (for, for example, certain kinds of traffic or at specific times)
    Restricted acces: traffic sign prohibiting a right turn during rush hours


Security issues where this measure can be effective and influenced by the urban planner, are:

Financial gain Boredom or compulsive behaviour Impulse Conflict in beliefs
Burglary{{#info:Burglary is the crime of illicitly entering a building with the intent to commit an offence, particularly (but not limited to) theft.}} Physical assault{{#info:Assault, is a crime which involves causing a victim to fear or to experience any type of violence, except for sexual violence}} Destruction by riots{{#info:Destruction by riots is the act of vandalism of property by organised groups for a shared rational or rationalised reason.}} Mass killing{{#info:Mass killing is the crime of purposely causing harm or death to a group of (unknown) people in order to make a statement or to influence the public opinion. This threat is exerted out of wilful action by fanatics: terrorists or criminal activists.}}
Ram-raiding{{#info:Ram raid is a particular technique for burglars to gain access to primarily commercial premises, by means of driving -usually stolen- vehicles into locked or closed entrances, exits or windows.}} Sexual assault{{#info:Sexual assault is assault of a sexual nature on another person, or any sexual act committed without consent}} Destruction of property by fanatics{{#info:Destruction by fanatics is the crime of purposely causing damage in order to make a statement or to influence the public opinion.}}
Pickpocketing{{#info:Pickpocketing is a form of theft that involves the stealing of valuables from a victim without their noticing the theft at the time. }} Vandalism{{#info:Vandalism is the act of wilful or malicious destruction, injury, disfigurement, or defacement of property without the consent of the owner or person having custody or control.}}
Robbery{{#info:Robbery is the crime of taking or attempting to take something of value by force or threat of force or by putting the victim in fear. It is used her exclusively for acts committed to individual persons.}} Graffiti{{#info:Grafitti is the defacement of property by means of writing or drawings scribbled, scratched, or sprayed on a surface in a public place without the consent of the owner or person having custody or control. }}
Raid{{#info:Raid is the crime of taking or attempting to take something of value from a commercial venue by force or threat of force or by putting the victim in fear.}} Antisocial Behaviour{{#info:Antisocial behaviour is an accumulation category of relatively small crimes that highly influence the security perception of citizens. }}
Vehicle theft{{#info:Vehicle theft is the crime of theft, or attempt of theft of or from a motor vehicle (automobile, truck, bus, motorcycle, etc.).}}
table to be updated if security issue pages finished


General considerations

For measures on traffic flows to be effective, the measures should match the docility of the targeted traffic flows. For instance, an average fence can be very effective against the average pedestrian, but less effective against an motivated vandal and hardly effective at all against a fanatic terrorist. In an urban context, the realisation form of a measure should conform to the targeted public, threat level and surroundings: high, unfriendly walls will be inappropriate in a shopping area and low, open fences are inappropriate for high-risk objects.

Urban planning considerations

Directing traffic flows provides a useful mechanism for reducing ease of opportunity for crime. Where possible, access to vulnerable areas (such as residential estates) should be restricted to as few routes as possible and should be designed to serve the development rather than through traffic. Unrestricted opportunities to enter, familiarise, offend and escape should be avoided. However any effort to direct traffic flows must take accessibility for emergency vehicles into consideration.

Safety/security considerations

When directing traffic flows, its impact on traffic safety should always be considered.

Social considerations

<designing out - decreasing attractiveness of environment>

Economic considerations

Directing traffic flows does not only reduce the potential impact of security threats, but also requires time and money by private agents, companies/developers and the public authorities, exacting economic costs. Together, the benefits and costs are referred to as economic impact of security measures. The costs of traffic flow management measures contain the relatively straightforward direct expenditures on capital equipment and operational costs (both temporary and permanent), and in addition generate various types of secondary effects.

In general traffic flows that are being managed will be more robust than in the opposite case. One should bear in mind though that at the same time traffic will be limited as well. This as a result of this traffic flow directing. Traffic rules such as speed limits, for example, aim to improve safety and the robustness of the road network, but at the same time increase travel time for road users Since they cannot drive as fast as wished for in all cases). Indirectly, this limited accessibility could lead to negative economic effects as a result of the less efficient transportation of goods, skills and persons. These negative impacts will reduce the functioning of the markets in the local economy, reduce the functioning of labour markets and attribute to less scale and agglomeration advances due to a decreased market size.

Whether the costs are making sense from an economic point of view, depends on many factors, and can be answered by two distinct sets of questions:

  1. Are the envisioned measures cost effective from a socio-economic point of view, or are there better alternatives?
  2. Which specific agents (individuals, companies, sectors, authorities) are affected by the specific measures, and to which extend? How do the envisioned measures adjust the behaviour of these agents, and of course the behaviour of criminals/terrorists?

Economic tools can help the decision makers to answer these questions and to prevent wasteful expenditures on security (of course in collaboration with insights from criminology, sociology, etc.).

Mobility considerations

An essential aspect for effectively closing or discouraging pathways is that an alternative route should be available and clear.

<restricting traffic flow>

Ethics considerations

Legal considerations

Footnotes and references

  1. For example, when a certain route is congested, the traffic can be guided to an alternative route with a dynamic route information panel (DRIP). The measure is also applied to increase safety, such as for instance to prevent flows of traffic from colliding, manage crowds or to support evacuation management in case of emergencies.