Italian drivers speed along on the right hand side of the road, but trains run on the left. With both road and rail present on the Messina Bridge there has been concern about the potential consequences of a 'cross-modal' crash. The combined speed of a train and car travelling in opposite directions could be 200km/h or more.
To reduce the hazard, the design team has switched traffic flows from right to left. As a result, slow vehicles will occupy the lanes closest to the rail track and run in the same direction as trains. Drivers travelling at speed will be in the outside lanes where they pose least danger.
Brown notes the right-left switch also suits the tracking and suspension of Italian cars, which are set up for the camber found on Continental highways. On Messina, the road lanes slope towards the bridge's centre line - a reverse camber.
There were fears that without crossing carriageways cars would have a tendency to veer towards the rail line.