The National Roads Authority has apologised and admitted its emergency procedures were not quick enough when the closure of one lane of the Dublin Port Tunnel caused traffic gridlock yesterday morning.
The failure of a height detector at the southern end of the tunnel at 6.20am contributed to mayhem which caused delays of up to two hours for motorists on the northside of the city.
The delay was described by Minister for Transport Martin Cullen as "unacceptable". "I'm not satisfied at all that it took so long to fix," he told the Oireachtas transport committee.
The failure set off the red light to the entrance of the tunnel and it took the NRA 2½ hours to fix the problem, which was caused by a computer error.
The delay was raised in the Dáil yesterday, with the Taoiseach saying the chaos which ensued actually proved that the tunnel works.
"It shows the huge success of the tunnel in only a few months that as soon as there was a delay everything happened," he said.
NRA spokesman Seán O'Neill said its engineers had first tried to fix the software, but then had to go on site to remedy the problem.
The NRA will be reviewing its procedures to see what lessons can be learned from yesterday's closures, he added.
"For safety reasons the tunnel was shut down, but we want to shorten the timetable down. The impact should not have been as significant as it was. There was a negative impact on traffic and we apologise for that, but we did not want to risk lives. We will do a full systems review in response to that incident."
Both the AA and Fine Gael have called for a full review of yesterday's incident - the first time the port tunnel was closed since it became fully operational in December.
Fine Gael transport spokeswoman Olivia Mitchell said it "defies understanding" that such an expensive piece of infrastructure as the port tunnel does not "have a plan B when disaster strikes".
AA public affairs manager Conor Faughnan said: "We've suddenly become very reliant on the port tunnel and, when it fails us, it can cause mayhem. You can't criticise the NRA for sticking to safety protocols, but it is worth an assessment to see if there are ways in which we can manage these things better and manage the time off line."
