There are so many great things about summer—longer days, beach vacations, music festivals and wearing shorts and flip-flops, to name a few–that it’s hard to think of a negative. But, when people take vacations and kids are off school, the roads fill up with more vehicles than during other months, and certain parts of the country see a huge increase in traffic as tourism booms. People generally just spend more time outdoors during the summer, and as a result, the number of vehicle accidents increases proportionally.

In addition to the greater number of motorists on the roads, a corresponding increase in runners, walkers and especially cyclists make the roadways a greater hazard during the summer months. A quick look at the streets of Philadelphia in July will reveal many more people walking, cycling and tooling around on motorcycles than in December, for instance.

One of the elements that make the road more dangerous during summer is the near-constant glare caused by the sun, which hangs in the sky longer during the extended daylight of summertime. Sun glare can affect how well a motorist sees lane markings, brake lights on the vehicle ahead, cars in lanes on either side, signal lights and stop signs (a real problem depending on the age of the traffic light!) and cyclists or pedestrians crossing the street. The sun can blind a driver to all of these everyday hazards, and certain traffic lights are almost impossible to read for red, yellow or green when the sun’s light refracts off their surface.

Intersections are an especially dangerous area during the summer months, as the glare of the sun makes visibility extremely difficult, especially at certain hours of the day. A couple of steps that motorists can take to reduce the impact of the sun’s glare are: 1) clean the windshield and windows often to reduce the effect of glare; 2) wear sunglasses to block many of the sun’s distracting rays.

Another factor involved in the rise of car accidents during the summer is the increased presence of teen drivers. These drivers are out of school and hitting the road, visiting friends, driving to jobs or just cruising to see and be seen. Their mere entry onto the streets of Philadelphia and surrounding suburbs dramatically increase the danger of driving in the area.

In a recent survey in California, for instance, teen drivers were at fault in 2/3 of fatal car accidents, an astounding number. It’s even more shocking when one realizes that teens comprise only 4% of licensed drivers in the state.

The nation’s birthday—July 4—is actually the most dangerous week of driving during the entire year for teen drivers. The four days surrounding that holiday see the highest number of fatal car accidents involving teens. Various organizations urge parents to remind their teens that they should always wear a seat belt, obey speed limits, ignore cell phones and never drink and drive.

Despite the efforts of parents nationwide, many end up heartbroken as vehicle accidents still stand at the top of the list for cause of death among people aged 15 to 20. That percentage of death caused by accident rises during the summer months.

Other factors that help to boost summer accident rates include distraction due to women wearing less clothing and thirstier drivers who drink alcohol in larger quantities. There is not any hard scientific evidence to prove that men seeing women in skimpier outfits distracts them while driving, but a recent poll in the United Kingdom showed that nearly 30% of men admitted to this practice. The higher percentage of men being involved in summer car accidents lends weight to this possible cause, as the phenomenon of higher accident rates for men demands some sort of explanation.

In addition to wandering eyes while behind the wheel, men (and women) drink larger amounts of alcohol as they exert themselves on summer days and have work up a thirst. More alcohol consumed means a greater likelihood of driving while impaired, which always causes more accidents.

Enjoy summer despite some of the statistics mentioned above. Get out and take advantage of longer days, festivals in the park, baseball games and family cookouts. Just remember that summer should bring a heightened awareness while driving of the many possible scenarios for a vehicle accident, ranging from the sun’s glare to the multitude of teen drivers to bars doing more business as people quench their thirst after a company softball game, then get on the road to go home.