Seven stretches of motorway across England have gone dark from midnight to 5am, to save electricity and reduce carbon emissions.

The Highways Agency has turned off the lights on patches of road which see little traffic in the wee hours of the morning and which have good safety records, too. The lights stay off until 5am.

The latest switch off will happen this week – on an eight-mile section of the M6 between junction 27, near Wigan and junction 29 (Lostock Hall). Other locations include the M4 near Bristol and the M5 at Exeter. And more are likely if feedback from the latest switch-off is favourable.

The lights remain on at junctions and elsewhere they can be turned on for road works or if there is an accident. The move, says the Highways Agency, cuts CO2 emissions and reduces glare for those living near motorways.

However, it will reduce this body’s £15m electricity bill by only a tiny amount and won’t actually save it money for now because extra equipment is needed so that the lights can be controlled for a regional command centre.

Environment campaigners welcome the initiative. But a report last year found that street lighting across all roads reduced fatal crashes at night by more than three-quarters and for this reason the Automobile Association has asked that the accident records of the newly dark roads are closely watched.

Many councils are also considering turning off lights on A-roads for part of the night to save money. Norfolk county council has said it intends to turn off 27,000 lights between midnight and 5am, saving £167,000 a year.