Spring is pothole season so you are seeing them everywhere. So why are there more potholes on residential and commercial streets than interstate highways?
There is a lot of money in potholes, but don’t count that as a good thing. The money goes to people other than the driver who has the unfortunate experience of hitting one with their car. Repair shops will sell or repair more tires ($100-$300), wheel rims ($75 to $150 for a repair, up to $500 to replace), broken wheels ($200–$500), realignments ($200-$500), damaged suspension components ($1000-$5000), bent steering parts ($300-$1500), and ruined shock absorbers ($150-$300 per shock) when a car is damaged by a pothole direct hit.
There are some car brands that withstand potholes better than others, as reported here previously.
There’s also money that it costs municipalities, states, and federal highway administrators to repair potholes – about $35 to $50 per pothole in materials and labor, assuming many potholes are being repaired with efficiency by the same crew from the same truck on the same day.
But for whatever it’s worth, you’re more likely to hit a pothole on a city street or commercial roadway – or even just in a parking lot – than when driving on a highway. Why is that?
Not every type of pavement is the same
In simplest terms, interstate highways are built to higher standards, able to handle heavy vehicle traffic. Road builders use stronger, more durable materials able to withstand the constant stream of heavier semi-tractor trailer trucks. A good way to understand the difference is how a long-haul truck, when empty, weighs between 18,000 and 25,000 pounds. Add several tons of cargo and the weight increases by as much. The average SUV, in comparison, weighs 5,000 to 6,000 pounds (plus human occupants, groceries, and maybe a Golden Retriever).
What this means is the roads handling lots of heavy vehicles need to be built to be more resilient – basically, the interstates where goods are transported coast to coast, north to south, and on all the byways in between. The Federal Highway Administration’s guidelines for highway pavement requires a minimum thickness of 10 inches thick for concrete (and in particularly heavily-trafficked sections, 12 to 14 inches), and three inches with asphalt.
In comparison, the pavement thickness on an average American city street is 6 inches for concrete and two inches for asphalt. This varies by climatic region and expected traffic volume – one of the reasons why heavy commercial trucks are limited by weight from traversing some streets.
Both types of roads will deteriorate with time, weather, and traffic. What causes small cracks also allows in moisture. When that moisture expands when frozen it pushes apart small cracks, leading to larger cracks – and ultimately, potholes
Beware where the road runs low
The type and purpose of a road isn’t the only factor that leads to potholes. The biggest enemy of pavement integrity is water – and water always trickles down. This then makes areas under bridges or viaducts – or any dip in the natural topography, where storm water might accumulate due to inadequate drainage – most vulnerable to potholes.
A driver approaching a dip in the road should always be on the lookout for potholes. They are more likely to happen there than anywhere else.
How you drive matters, too
To keep more money in your pocket and leave less at the car repair shop, it makes sense to drive cautiously on all types of roads and highways. This holds true particularly during the late winter-early spring period when the ravages of winter freeze-thaw cycles cause more potholes to appear than any other time of year.
Puddles might be potholes in disguise. You’ve heard still waters can sometimes run deep? That glassy oval on the road might be 9 inches of water over a 2 foot wide pothole.
Tire inflation. This is the kind of inflation that can save you money from flat tires. When the tire is underinflated, it’s more likely a direct hit on a pothole will cause a tire puncture.
No fast moves. Whether it’s a swerve, a sudden slam on the brakes, or even just driving too fast, each of these things can be damaging to your vehicle. If a pothole hit appears to be inevitable, better to ride over it and, as soon as possible, pull over to inspect your tires for damages. Sometimes the damage is not visible to the eye, but result in a flat tire miles down the road.
Above all, be patient with the conditions of roads and highways when driving during pothole season. Those potholes will be filled eventually – and your money is more likely to stay in your pocket.