Mixture of rain and oil on the road creates dangerously slippery conditions

Dangers from Driving in the Rain Increase After Dry Spell

Rainy weather does have an adverse effect on driving conditions; however, the risks actually decrease if it had rained the previous day. Daniel Eisenberg of the University of California, Berkeley found that a heavy shower after a dry spell causes a sharp increase in accidents. His research suggests that during a drought, engine oil and grease build up so that when it rains the oil and water mix causing extremely slippery conditions. In addition, people are also not as prepared for these conditions after a long dry spell. Therefore, the most important factor is probably motorists driving in heavy rain as though it were still dry and tailgating other vehicles. Eisenberg hopes his research results will persuade highway authorities to warn motorists of the added danger when it rains after a drought.