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Here's How Much Traffic Congestion Costs the World's Biggest Cities

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Traffic congestion isn't just a nuisance for the people who get trapped in gridlock on their way to work, it’s also a problem for a city's economy, City Lab reports. According to a study from the transportation consulting firm INRIX, all that time stuck in traffic can cost the world’s major cities tens of billions of dollars each year.

The study, the largest to examine vehicle traffic on a global scale, measured congestion in 1360 cities across 38 countries. Los Angeles ranked number one internationally with drivers spending an average of 102 hours in traffic jams during peak times in a year. Moscow and New York City were close behind, both with 91 lost hours, followed by Sao Paulo in Brazil with 86 and San Francisco with 79.

INRIX also calculated the total cost to the cities based on their congestion numbers. While Los Angeles loses a whopping $19.2 billion a year to time wasted on the road, New York City takes the biggest hit. Traffic accounts for $33.7 billion lost by the city annually, or an average of $2982 per driver. The cost is $10.6 billion a year for San Francisco and $7.1 billion for Atlanta. Those figures are based on factors like the loss of productivity from workers stuck in their cars, higher road transportation costs, and the fuel burned by vehicles going nowhere.

Congestion on the highway can be caused by something as dramatic as a car crash or as minor as a nervous driver tapping their brakes too often. Driverless cars could eventually fix this problem, but until then, the fastest solution may be to discourage people from getting behind the wheel in the first place.

[h/t City Lab]

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Big Questions
How Are Speed Limits Set?
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When driving down a road where speed limits are oppressively low, or high enough to let drivers get away with reckless behavior, it's easy to blame the government for getting it wrong. But you and your fellow drivers play a bigger a role in determining speed limits than you might think.

Before cities can come up with speed limit figures, they first need to look at how fast motorists drive down certain roads when there are no limitations. According to The Sacramento Bee, officials conduct speed surveys on two types of roads: arterial roads (typically four-lane highways) and collector streets (two-lane roads connecting residential areas to arterials). Once the data has been collected, they toss out the fastest 15 percent of drivers. The thinking is that this group is probably going faster than what's safe and isn't representative of the average driver. The sweet spot, according to the state, is the 85th percentile: Drivers in this group are thought to occupy the Goldilocks zone of safety and efficiency.

Officials use whatever speed falls in the 85th percentile to set limits for that street, but they do have some wiggle room. If the average speed is 33 mph, for example, they’d normally round up to 35 or down to 30 to reach the nearest 5-mph increment. Whether they decide to make the number higher or lower depends on other information they know about that area. If there’s a risky turn, they might decide to round down and keep drivers on the slow side.

A road’s crash rate also comes into play: If the number of collisions per million miles traveled for that stretch of road is higher than average, officials might lower the speed limit regardless of the 85th percentile rule. Roads that have a history of accidents might also warrant a special signal or sign to reinforce the new speed limit.

For other types of roads, setting speed limits is more of a cut-and-dry process. Streets that run through school zones, business districts, and residential areas are all assigned standard speed limits that are much lower than what drivers might hit if given free rein.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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School Buses May Soon Come with Seat Belts
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The days of school bus passengers riding unencumbered by seat belts may soon be over. This week, the federal National Transportation Safety Board made a recommendation to state agencies that new, larger buses should come equipped with lap and shoulder belts, as well as automatic emergency braking and anti-collision systems.

Traditionally, most large school buses have allowed students to ride without being secured in their seats. That’s because the buses are designed to surround passengers with shock-absorbing, high-backed seats spaced closely together, an approach referred to as "compartmentalization." In an accident, kids would be insulated in an egg-carton type of environment and prevented from hitting a dashboard or window. For smaller buses—usually defined as weighing 10,000 pounds or less—belts are standard.

The Safety Board’s conclusion comes at a time when recent bus crashes—including one with two fatalities that took place in New Jersey just last week—have reopened discussion as to whether larger buses need belts. The National Highway Traffic Safety Administration maintains that the compartmentalization of larger buses provides adequate safety, while the American Academy of Pediatrics argues that belts should be mandatory on all buses in the event of high-speed collisions or rollovers, where the high-back seats would offer less protection.

For now, the National Transportation Safety Board’s suggestion is just that—a suggestion. No states are required to follow the advice, and there’s considerable expense involved in retrofitting older buses with belts. Currently, eight states require seat belts on large buses.

[h/t ABC News]

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