Vehicle activated sign

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Vehicle activated sign (VAS) is a generic term for a type of road traffic sign which displays a message conditional upon the presence, or speed, of a road vehicle.

Contents 1 Sign types 1.1 Speed enforcing 1.2 Hazard warning 2 Sign Effectiveness 3 References 4 Notes

[edit] Sign types

[edit] Speed enforcing

These signs activate if an approaching vehicle is detected to be exceeding a preset speed threshold. The speed limit and/or a warning message will illuminate on the sign to remind the driver/rider to slow down.

[edit] Hazard warning

These signs are installed on the approaches to hazards such as bends and junctions. If triggered they may display a warning message and/or an image of the appropriate road sign (sharp bend, junction, etc).

[edit] Sign Effectiveness

In a study^[1] conducted by TRL for the UK Department for Transport one of the conclusions was that vehicle activated signs appear to be very effective in reducing speeds; in particular, they are capable of reducing the number of drivers who exceed the speed limit and who contribute disproportionately to the accident risk, without the need for enforcement such as safety cameras.

[edit] References

• Traffic Activated Signs UK Department for Transport website

[edit] Notes

1. ^ Winnett, M.A., Wheeler, A.H. (2002). "Vehicle-activated signs – a large scale evaluation (TRL548)". . TRL