Birmingham's Bordesley Circus roundabout is one of the most dangerous in Britain - with an accident every 20 days over the last six years.
The roundabout, which links the A45 Coventry Road to the middle ring road, is the second most dangerous roundabout in the country.
Latest Department for Transport figures show that there have been no fewer than 105 accidents between 2010 and 2015.
Birmingham's roads chief says that should change as works to install traffic lights, and to create what is known as a "hamburger" roundabout – running a road through the middle – were completed earlier this year. The new route across the island speeds up the traffic from the A45 Coventry Road joining the ring road.
New traffic lights at Edgbaston's Five Ways should also improve safety at the city's second most dangerous island, scene of nearly 50 accidents.
Labour roads chief Stewart Stacey said: "These are two of the busiest roundabouts in Birmingham.
"We had already identified that there were issues at both and successfully secured funding for major improvements to reduce accidents and congestion.
"Works at Bordesley Circus, to create a 'hamburger junction', were completed in March this year, while new traffic signals were installed at Five Ways island last year.
"All safety improvements are monitored to evaluate their effectiveness but it is too early to say whether these improvements will have the full effect anticipated.
"In the meantime, I urge all motorists to drive with due care and consideration, to keep Brummies and other road users safe."
The improvements to Bordesely Circus and Five Ways were part of a £14 million improvement to the ring road's traffic "pinch points" and designed to ease congestion, as well as improve safety for motorists, cyclists and pedestrians.
Salford Cirucs, under Spaghetti Junction, also saw traffic signals installed last year in a bid to cut accidents and improve traffic flow.
Previous accident hotspots in Birmingham, such as the Shenley Fields Road/Middle Park Road junction in Weoley Castle and the Solihull Hospital roundabout have dropped out of the top five list in the past 12 months.
Overall analysis of government data also uncovered an increase in accidents on roundabouts in the West Midlands in the past year, with Coventry seeing a 48 per cent increase, Birmingham a 12 per cent rise and Sandwell eight per cent.
The other four metropolitan boroughs – Dudley, Solihull, Walsall and Wolverhampton – saw decreases between 2014 and 2015.
Nationally, accidents fell by 5.8 per cent but the number of fatal accidents on UK roundabouts increased from 30 to 54.
Only the roundabout at the Elephant and Castle tube station in Southwark, London, is more dangerous than Bordesley Circus, with 163 accidents in six years.
West Midlands' Five Most Dangerous
1. Bordesley Circus (105 accidents)
2= Edgbaston Five Ways (49)
2= Birmingham Road/M5 island, Sandwell (49)
4= Cinder Bank Island, Dudley (37)
4= Salford Circus, Spaghetti Junction (37)
4= Belgrave Interchange (37)
(Accidents 2010 to 2015)