Motorcycle accidents were the leading non-combat cause of death for US service members. Between 1999 and 2012 4,423 died in combined motor vehicle deaths including motorcycles. Of those 1,134 died in motorcycle crashes. Between 2001 and 2008, the portion of fatalities from motorcycles tripled, and by 2008 was almost 40% of overall vehicle fatalities. Motorcycle deaths have come under increased attention because other types of non-motorcycle fatalities have decreased, so motorcycle fatalities became an increased share of deaths. The fatalities echoed the national statistics with motorcycle fatalities of 4,927 deaths being 15 percent of all traffic deaths in 2012, even though motorcycles are three percent of vehicles. However, they account for a relatively smaller amount of the total miles traveled (motorcycles are often only driven in good weather) about 0.7% of all vehicles miles traveled 2012. (About half a million people to a million people would die each year if cars had a similar accident rate, all else being equal.) 93% of the crashes in 2012 involved a two-wheeled motorcycle. (see also Motorized tricycle) Of 4,957 killed in 2012 on motorcycles, 7% were passengers. Combined driver and passenger deaths for motorcycles were 18% of all driver and passenger deaths in 2012 for all vehicles. This is for just 0.7% out of all vehicles miles driven in the US that year. Types of accidents and injuries By 2014 a rear-ending occurred every 17 seconds on the US road system, and improvements to cars especially in regards to headrests have reduced whiplash and other neck and back injuries related to this. One hope may be Collision avoidance systems on more vehicles. However, it is head-on collisions with cars that make up one of the biggest types of fatal collisions. Of the 56% of fatal collisions with other vehicles, 78% percent were head-on collisions and 5% were a fatal rear-ending of the motorcycle by another vehicle type. Of those fatal head-on collisions one of the most common is when a car makes a turn and another situation is when a motorcycle is trying to pass another car. In 2012, 75% of two-vehicle motorcycle accidents involved the motorcycle crashing into the vehicle ahead of it and only 7% involved the motorcycle being hit in the rear. That year half of all fatal accidents were two-vehicle crashes, However, they also had the highest rate of collision with fixed object between passenger cars, light trucks, and