Road network density and number of cars
Thailand has a 200,000 km road network. According to worldstat.info, that makes the road network density (km of roads per 1,000 km²) of Thailand similar to the one of New Zealand.
The total number of vehicles was estimated to 20 million in 2006 (source: ESCAP), and the number of cars (including SUVs, vans, and commercial vehicles) was estimated to 11.2 million in 2011 (source: Wikipedia). There are 165 cars per 1,000 inhabitants in Thailand, the same number as in South Africa (by comparison there are 712 cars/1,000 people in New Zealand and 797 in the USA).
Road accidents fatalities
Each year, about 13,000 people die in road accidents in Thailand, and several hundred thousands are injured (source: ESCAP). The death rate per 100,000 inhabitants is 19.6 in Thailand (source : Wikipedia), which is a figure similar to Russia (19.5) or Brazil (19.9). As a comparison, the rate is 12.3 in the USA, 5.5 in France, 3.6 in the UK and only 2.9 in Sweden). New Zealand, which has a similar road network density, has a death rate per 100,000 people of 8.6, and South Africa, which has a smilar number of cars on the roads, has a rate of 33.2. The most dangerous countries are Eritrea (48.4), Cook Islands (45.0), Egypt (42.0) and Libya (40.5).
Other interesting facts
Most accidents and most fatalities happen in urban areas. In 2005, 59% of accidents happened in Bangkok (but the number of deaths was 13% of the total).
While the traffic decreases during the night, the number of accidents doesn’t drop at the same pace. Most accidents happen during morning and evening rush hours, but at night a peak can be noticed between 18.00 and 21.00. It can be explained by drunk driving (in Thailand people who drink on a regular basis start early in the evening).
For further reading, we recommend this 2006 report written for the ESCAP (the United Nations Economic and Social Commission for Asia and the Pacific).