The government’s announcement that it will stop building new smart motorways following concerns about cost and safety has put the focus on those already in place. Smart motorways were designed to ease traffic flow, partly by some of them using the hard shoulder as an extra lane for vehicles. Critics claim they have led to road deaths.
What is a smart motorway?
A smart motorway is a stretch of road where technology is used to regulate traffic flow and – hopefully – ease congestion. There are three main types:
- controlled, which have a permanent hard shoulder, but use technology such as variable speed limits to adjust traffic flows dynamic, where the hard shoulder can be opened up at peak times and used as an extra lane; when this happens, the speed limit is reduced to 60mph
- all-lane running, where the hard shoulder has been permanently removed to provide an extra lane; emergency refuge areas are provided at regular intervals for cars that get into trouble
- All three models use overhead gantries to direct drivers. Variable speed limits are introduced to control traffic flow when there is congestion, or if there is a hazard ahead. These limits are controlled by speed cameras.