Birmingham A38 tunnels close again for work over the summer
Road tunnels through Birmingham City Centre have closed for six weeks for the second summer in a row.
Renovation work will see ventilation systems replaced in the A38 St Chad's and Queensway tunnels along with new security, CCTV and communications.
Low-price rail and bus passes are being offered to ease commuter traffic until the tunnels reopen on 6 September.
Transport firms said more than 200,000 extra journeys were made on public transport during last year's closures.
Refurbishment of the 40-year-old tunnels is being carried out by contractor Amey and will also see new electrical systems installed.
Overnight closures have been in place since the beginning of the month.
Last summer many experts predicted widespread chaos, with the tunnels regularly used by about 85,000 vehicles a day.
A report to the city council in November, however, said the road system had coped better than expected.