Electronic Message Signs
These signs provide advance warning to drivers of emergencies, incidents and road management. They are aimed at improving safety and minimising the impact of congestion (see also “Variable Message Signs”).
Electronic Road Pricing (ERP)
A demand management strategy aimed to reduce auto travel in selected areas and along certain routes within congested periods. Introduced in Singapore in 1998, the system is based on a pay-as-you-use principle and motorists are automatically charged during peak hours. A device known as an In-vehicle Unit (IU) is placed on the lower right corner of the front windscreen within sight of the driver, in which a stored-value card, the CashCard, is inserted for payment of the road usage charges. It is mandatory for all Singaporean vehicles to be fitted with an IU if they wish to use the priced roads.
A freeway or expressway lane used for faster moving traffic and has less access to exits/off ramps.
Express Toll Lane (ETL)
A type of road pricing system where motorists may pay a toll to gain access to lanes that are separated from the mainstream traffic. Typically, these tolls will increase as traffic density within the tolled lanes also increases. This pricing scheme limits the traffic demand within the lanes, ultimately resulting in lanes that can travel freely despite the congestion in the mainstream travel lanes.
Expressway – US
A divided highway for high-speed traffic with at least partial control of access.