Traffic Schemes

Traffic management schemes include traffic signal controlled junctions, parking regulation, traffic calming, pedestrian and cycle route improvements and road signing.  They are introduced to solve a traffic related problem in one or more roads.  The need for a scheme can be identified in a variety of ways.  It may, for example, be a bad casualty record or the concerns of residents that prompts an investigation.  Potential schemes are assessed and prioritised against the following criteria:

• to achieve safe movement by reducing accident levels
• to promote and accommodate the maintenance and improvement of public transport
• to restrain traffic and safeguard the environment
• to seek equitable levels of mobility and accessibility for all groups of people, particularly for those presently disadvantaged in mobility terms e.g.  people with disabilities, children, the old and the infirm
• to reduce the impact of commuter parking
• to improve pedestrian safety, accessibility and convenience
• to promote cycling

Solutions can include:

"Chicanes" and "Throttles"

Chicanes and throttles are intended to reduce traffic speed by reducing the available carriageway width throughout a short length.  Chicanes introduce a physical deflection into the vehicle's direction thereby further reducing the vehicle speed.  Throttles narrow the road, frequently to provide a safe crossing point for pedestrians, sometimes in conjunction with a speed table.

Problems can occur, however, where opposing traffic flows are low, and certain types of driver view them as a 'challenge' to their driving skills.  In the past this has resulted in inappropriate speeds and reckless driving.

Kerb build outs

At some road junctions visibility is often reduced because of the shape of the road or because of parked cars.  Building out the kerb into the carriageway can help solve this problem.  It provides protection for motorists emerging from a side road as they can safely pull further out to see, and be seen.  Pedestrians are similarly protected, have more space to stand and can also see and be seen better.  Cars are forced to park further from a junction or crossing point.

Road humps, speed cushions or speed tables

Width restrictions

Width restrictions are a self enforcing means of restricting access for large vehicles.  Posts, bollards or kerbs are placed in the road about 2.1 metres (7 feet) apart, such that vehicles wider than this cannot pass between them.  There must be an alternative route available for large vehicles such as refuse collection vehicles and this sometimes limits their application in residential areas.

One Way streets, banned turns and No Entry

These help control traffic movements, without completely restricting access.  They can stop commuter "rat-runs" which occur.  One-way working may be for the whole length of a street, or in a short length at one end.
 
A suitable alternative route must be identified and available for traffic travelling in the opposite direction to the one-way street, or for traffic needing to turn in the direction of the ban.  This alternative would quite often be another residential road, which may in turn create problems for another group of residents.
 
One-way streets often lead to an increase in traffic speed.  Short lengths are difficult to enforce if drivers are irresponsible and determined enough to drive against the one-way.  This is dangerous and illegal.  Some residents find one-way streets and banned movements inconvenient as they may result in reduced levels of access to their homes

Road closures

These are an effective, self-enforcing, means of stopping all through traffic movements.  Roads are usually closed by kerbs and bollards, which will have a detrimental effect on emergency access by Police, Fire and Ambulance vehicles.
 
Near to a road closure, it is necessary to make provision, on either side, for large vehicles to turn round.  That is why it is not used in many residential areas.  It may also be inconvenient to some residents as Road Closures limit access.

Standard roundabouts

These are very well established features of road design aimed at improving flow and reducing conflicts at junctions.  Roundabouts also incorporate traffic calming features such as giving way to other traffic and a form of chicane and special provisions for pedestrians and cyclists.  As such it may be advantageous to incorporate roundabouts into traffic calming schemes.  Roundabouts are good effective ways of altering a junction's priority and therefore slowing traffic that before had priority.

Mini roundabouts

Mini roundabouts are introduced both as a means of reducing accidents, by slowing traffic, and to assist right turning movements.  Their advantage over full size roundabouts is that they can often be accommodated within the existing road space, without expensive road widening.  As at a full size roundabout, the rule at a mini roundabout is "give way to traffic from the right".

Pedestrian crossings

The Council installs or upgrades several pedestrian crossings (i.e. zebra or signal controlled crossings) each year.  Each request is examined on its individual merits in line with set criteria in accordance with current County Council policy.  Many requests are not justified due to low levels of pedestrian movement.

The following factors are taken into consideration in assessing the need for a crossing:

• the record of personal injury accidents involving pedestrians
• the volumes of vehicular traffic and pedestrian demand and the potential for conflict between pedestrians and vehicles
• the difficulty that pedestrians face from traffic speed and volumes
• the length of time pedestrians have to wait before they can cross
• locations which attract pedestrian activity throughout the day e.g.  routes to school, proximity to local amenities

Puffin Crossings - these signalled crossings are used on roads which have high traffic volumes, high traffic approach speeds or very high pedestrian flows.  The time allocated for pedestrian crossing movement is dictated by Department for Transport's guidelines and is based upon the width of the road.

Zebra Crossings - these are used on roads with lower pedestrian or traffic flows.

Traffic islands/pedestrian refuges - these can be installed where a formal pedestrian crossing is not justified.  They assist pedestrians by allowing them to cross the road in two stages.  The restriction to the use of this measure is the width of the carriageway.  It must be of sufficient width to accommodate the island and two lanes of traffic.

Facilities for the Disabled

Tactile paving is now used at all new pedestrian crossings to help people with impaired vision.  Similar tactile paving is also used at many ramped crossing points.  Many single pelican or puffin crossings have audible signals, as well as the green man signal, to indicate when it is safe to cross the road.  Some staggered two stage pelican crossings and some junction signals are fitted with a tactile knob on the pedestrian push-buttons, rather than an audible signal.  This is so that visually impaired people can tell which part of the staggered crossing or junction is safe to cross.

Carriageway markings

Carriageway markings are a cheap and cost effective way of reducing accidents.  At junctions they provide an indication of priorities, and as centre or lane lines, they indicate the best line for vehicles to follow.  White markings are generally advisory.

Lane arrows are used on the approaches to traffic signalled junctions to indicate which lane should be used for turning and straight ahead movements.  Lane arrows are generally not permitted on the approaches to roundabouts.  SLOW markings are often used on the approach to a hazard.

Areas of central cross hatching, commonly called "ghost island" markings, are useful as a means of reducing accidents by separating on-coming traffic, reducing traffic speed and providing safe right turning areas.
 
Continuous white centre line markings must not be crossed and are generally used to prevent overtaking and reduce speeds in roads with poor visibility due to bends or the crests of hills.  These are also used sparingly so that they are more effective and have more impact when they are used.  There are criteria for the introduction of these markings based upon the speed of traffic and the visibility distances.

It is also an offence to park in any section of road that is marked with a continuous white line.  Continuous white lines may only be crossed by traffic that is turning right.

Yellow lines (waiting restrictions)

Residents' Parking Schemes

Traffic signals and control

Traffic signals are designed to optimise and control traffic at a junction by sharing out the time to different arms of the junction.  Phases are often included for pedestrians and cyclists.  Traffic signals do not always solve accident problems.

Coloured / Anti-Skid Surfacing

The objectives of traffic calming include improving driver awareness.  Normal 'black' road surfacing can be re-laid in different colours in order to heighten driver awareness.  Red is considered to be a particularly effective colour.  The impact of a feature like this relates to how unusual it appears to the road user.  For this reason it is prudent to be sparing in the use of materials which are designed to make an impact.

A further variation of both black and coloured surfacing is 'anti-skid'.  This material has a special and gritty surface texture designed to give particularly good resistance to skidding.  Anti-skid surfacing is often provided in a buff colour and is used at many locations (e.g.  pedestrian crossings, traffic signal controlled junctions) where traffic may stop abruptly.

Gateways

These are features at the entry to villages and towns, generally where the speed limit begins, to increase driver awareness.  They often consist of prominent signs and coloured surfacing, and may be accompanied by road narrowing and other features.  They are also used to introduce drivers to a 20 mph Zone and promote self-enforcement of the reduced speed limit.

20mph Zones

It is hoped that by introducing 20 mph zones in residential areas drivers will automatically slow their vehicle to a more suitable speed when they enter the area.  Developers of new residential areas are encouraged to design traffic calming/20 mph zones into their schemes.

To be effective a Zone has to have special features to make sure vehicle speeds are reduced.  These can include standard road humps, narrower humps known as 'cushions', road narrowings, pedestrian crossings or highway markings.  The residents and emergency services are fully consulted on all schemes and their views are taken into account in the detail design.

School Safety Zones

It is hoped that by introducing advisory 20 mph limits around schools drivers will automatically slow their vehicle to a more suitable speed when they pass the school.

Implementation of School Safety Zones hinges on the school, parents, children and the local community being supportive of this solution to reducing danger perception outside schools and providing a safer environment in which walking and cycling to school can be encouraged.  The main aims are to keep school frontages clear of parked vehicles and to reduce traffic speeds during school term times.  This depends on the road outside the school being suitable for treatment.