More than 3,000 high school and college students from 24 countries are gathered in the port city of Rotterdam, the Netherlands, this weekend for a race for fuel efficiency. More than 180 cars are entered in Shell Eco-marathon Europe 2013, where students design and build super-low-mileage vehicles, and then prove them on a 10-mile (16.3-kilometer) street circuit.

Rainy and windy weather has complicated the schedule, because the low-slung vehicles in the prototype category cannot compete in wet conditions. Their tires not only are slim, they are pumped to high pressure and have little grip on slick roads. A team from Salzburg, Austria nearly lost the cover over the driver’s cab in a strong gust of wind on one run, and the