Shortly after the Adelaide-Crafers section opened, several incidents involving semi-trailers drew media attention to the road. While the previous Mount Barker Road was a notorious stretch, its dangers were well known; the new freeway presented the new challenge of a sustained continuous gradient with traffic lights at the bottom. Heavy vehicles with inadequate braking found it hard to slow down once they had exceeded a certain speed; this was made worse with brake failures. It took some time, and the addition of several warning signs prior to the descent, for heavy vehicles to become familiar with the freeway's characteristics. Semi-trailers can be seen travelling as slow as 20–30 km/h downhill. In 2005 changeable electronic road signs were installed every 200 metres, so that the speed limit of the road can be adjusted from Transport SA headquarters in Adelaide. This has both improved safety for commuters, and emergency service workers like the Country Fire Service.