FOUR motorists drove up a tram-only viaduct in Nottingham in the space of just eight weeks – but no further action will be taken to stop it happening again.

All of the incidents at Middle Hill, near the Broadmarsh Centre, between November 19 and January 5, disrupted NET tram services and at least one was caused a person following directions given on a satnav.

The city council's accident investigation unit has looked into the issues to see if any improvements could be made to road signs and lines to stop it happening again.

NET director Pat Armstrong said: "This concluded that the control measures that are in place at present are more than adequate to alert the majority of road users that there is no entry for road traffic other than trams on to the viaduct."

These measures include a red sign at the entrance to the viaduct saying "no access to road vehicles."

The first incident happened at 9.32am on November 19, when, according to NET, the driver was reported to have followed the tram.

At 2.30pm on November 23 the driver was said to not look at the signs before heading up the track.

A driver who ended up on the viaduct at 12.05pm on November 28 could not explain why they had driven down the tracks.

And on January 5, at 11.03am, a driver claimed to have been following satnav instructions.

This incident caused tram delays of 25 minutes and they had to turn round in Old Market Square while the car was removed.

Nicola Tidy, a spokeswoman for NET, said satnav checks had been carried out on the road since the last incident.

"Satnav does not direct drivers down the tram track. We have specifically checked this," she said.

"It does say 'at the end of the road bear left.' It may be that people are misunderstanding this."

Andy Holdstock, a senior officer in the NET project office, said it was puzzling that drivers could miss the signs.

"From what we have heard, at least one of those people was following satnav and not following the signs," he said.

"It is difficult to work out what the problem is. The accident investigation people couldn't see any real problem.

"It seems people are getting confused. People do rely on their satnavs too much."

Andrew Howard, head of road safety for the AA, urged drivers to keep an eye on the road.

"For anyone using satnav, you are the driver and you have got to recognise what is out of your windscreen," he said.

"You have got to still look at the road signs and you have got to accept that things can happen that change the function of roads, even overnight.

"A lot of the time it seems to be that they are fairly obvious places where things go wrong. Whatever technology you are using you have got to rely, in the final analysis, on what you see."

Details of the incidents were to be discussed at the city council's Greater Nottingham Light Rapid Transit Advisory Committee today.

The meeting will also be told the service ran to an average of 99% reliability in November December and January, while overall punctuality fell slightly to 97% in the same period.

The principal reason was delays caused by traffic congestion in Radford Road, with cars queueing to gain access to Asda car park.