One factor that people often overlooked is that it's not physically possible to widen some of the most congested sections of the motorway network in the UK. The

One factor that people often overlooked is that it's not physically possible to widen some of the most congested sections of the motorway network in the UK. They are often over extended elevated sections, bridges, and tunnels. When it is physically possible, the cost is prohibitive. On balance, "Smart Motorways" can be safe - but poor driver behaviour is impossible to mitigate against. The automatic stopped vehicle detection should help things. The government has said that it will scrap the older "Dynamic Hard Shoulder" sections of motorway (where the hard shoulder is brought into use as a traffic lane during busy times only - which some drivers clearly don't understand), and replace them all with "All Lanes Running" systems, where there is simply no hard shoulder. That consistency should make it easier for drivers to know what to do in all cases, and help remove some of the accident risks. Stopping on the hard shoulder (where there is one) is very dangerous by itself - again, due to poor driver behaviour. The presence of a hard shoulder does not eliminate accidents.