The Asphalt That Has to Survive New Jersey Winters

Achyut Manoj
Jul 17
7 min read

In March 2026, as New Jersey's roads thawed from another winter, NJDOT launched its annual pothole campaign, mobilizing crews across the state to fill the tens of thousands of cracks and divots that emerge each spring. The potholes are not random bad luck or careless maintenance.

They are the predictable outcome of a cycle that repeats every year in every cold climate: water seeps into the road, freezes and expands, splits the asphalt, thaws and loosens the pieces, and leaves a hole. The engineering that goes into roads is meant to slow this cycle down. How well roads actually survive depends on what they're built from, how they're built, and how much money gets spent keeping them up. All three of those things are decisions, and all three are currently being fought over in Trenton.

How a Road is Built to Survive Freezing and Thawing

A road under your car is a carefully layered system. At the surface sits asphalt, a mix of crushed stone and a black binder called bitumen that holds it together. Underneath that is a base layer of larger crushed stone or recycled asphalt, which distributes the weight of traffic across a broader area and lets water drain away. Below that, on roads built to code, sits a subgrade: compacted soil that forms the foundation. This whole stack might be a foot or two thick, depending on how much traffic the road handles.

Managing water is the key to surviving winter. A properly built road slopes gently so rain and snowmelt run off sideways into ditches or storm drains rather than soaking straight down. Good drainage means water doesn't sit in the layers underneath the asphalt, where it can freeze, expand, and crack the surface above. A road also needs aggregate, the crushed stone, in the right mix of sizes. Smaller pieces fill gaps between larger ones, so less water can find its way into spaces. Asphalt itself also matters. Newer asphalt can be mixed to be somewhat flexible, designed to bend slightly as traffic and temperature push it rather than cracking.

That flexibility matters because New Jersey's temperature swings are brutal on pavement. A winter day might drop from 40 degrees to 20 degrees in an hour. When asphalt contracts, a heavy truck rolling over it at exactly the wrong moment can fracture the surface. Water gets in that hairline crack. At night it freezes, expands by about 9 percent, and widens the crack. By spring, that hairline has become a pothole several inches deep.

Salt plays a complicated role. Road salt lowers the freezing point of water, so brine rather than ice forms on the pavement. That's critical for safety since an icy road can cause accidents. But salt also accelerates the breakdown of asphalt itself and the concrete beneath it, and it seeps into groundwater that many New Jersey communities depend on. NJDOT alone spread more than 82,000 tons of rock salt on state highways in a recent winter, and that's before counting what counties and towns apply on local roads. That salt doesn't just go away; USGS research has linked road-salt application to rising radium and salinity levels in aquifers, particularly in low-pH groundwater found in parts of south Jersey.

Where Roads Are Failing Today

Much of New Jersey's road network was built in the mid-twentieth century, when traffic was lighter and climate was more predictable. Pipes don't age gracefully, and neither do roads. The American Society of Civil Engineers gave New Jersey's overall infrastructure a D+ in its 2025 report card and found that 18 percent of the state's roads are in poor or fair condition. That gap costs the average driver over $350 a year in extra vehicle repairs and operating costs, according to the group's estimates. Local roads, which account for most of the pavement New Jersey residents drive on, are often in worse shape than state highways because local governments have smaller budgets and less access to state or federal funding.

Potholes are the visible symptom, and they're more than an inconvenience. A pothole that deflates a tire can be expensive to fix, and one deep enough to break a wheel rim can damage a car enough to make it unsafe. Liability is unclear. New Jersey law gives municipalities some protection against pothole damage claims, so drivers often bear the cost themselves. Potholes also tell a story about maintenance cycles. A road filled with potholes is one where preventive work (patching small cracks before they become big ones) didn't happen or wasn't funded. By the time potholes appear, the road is already in trouble. You can fill them quickly with hot asphalt, but that's a cheap fix. Addressing what's wrong underneath is the right fix.

Underneath many roads, especially older ones, is something worse than potholes: a failing base layer or subgrade. Water has been getting in for decades. Saturated soil is weak soil, and you can't see it from the surface. A truck hits a weak spot and the pavement sags or breaks. In the worst cases, entire sections of road fail at once, and the only fix is to tear it out and rebuild.

The Solutions Being Tested

Some of the newer approaches to road durability come from thinking differently about what roads are made of and how water moves through them. Permeable pavement sounds like a contradiction since roads aren't supposed to let water through. But the idea is to let water drain through the surface in controlled ways, then filter down through base layers where it can be captured and reused rather than running off into storm drains. Permeable asphalt and concrete have been tested in cold climates and can reduce icing since water drains away instead of pooling and freezing. They can also reduce stormwater runoff, which is a separate environmental problem in cities.

Recycled asphalt is another option. When old roads are torn up for replacement, much of that material can be ground up and mixed into new asphalt or used in base layers. It's cheaper than virgin aggregate, reduces the need to mine new stone, and research suggests the recycled material performs well in freeze-thaw cycles. Some states have started requiring a percentage of recycled content in road projects.

Salt alternatives are gradually being adopted. Liquid de-icers based on brine can be applied more precisely than rock salt, so less ends up washing into groundwater. Additives like beet juice or pickle brine, tested in states like Minnesota and Connecticut, can lower the freezing point of water without as much saltiness. Some towns have started using sand mixed with minimal salt for traction rather than salt alone. None of these are silver bullets. They cost more upfront and don't work in the coldest extremes, but they reduce environmental damage without completely sacrificing winter safety.

Better maintenance cycles matter too. If a road is sealed and patched every few years, before cracks have time to grow, the pavement lasts longer. A road that's ignored until it's falling apart requires full reconstruction, which costs ten times more than the preventive work would have. The challenge is that preventive maintenance doesn't show up in a political cycle. A mayor who pays for patching doesn't see a payoff; the next administration gets the benefit of roads that don't need emergency repair. That mismatch between who pays and who benefits creates pressure to let maintenance slide.

The Policy Tangle

New Jersey's Transportation Capital Program funds projects across the state each fiscal year, but that money is split among new construction, maintenance, transit, and bridge work. Local roads (the ones most people drive on) compete with state highways and regional priorities for a limited pool. State role is also limited. While NJDOT can set standards and oversee highways, most road maintenance falls to municipalities and counties, which have their own budgets and political pressures. A town council that spends money on pothole repair is spending money that could go to schools or property tax relief. Incentives to defer are real.

Federal funding helps but comes with strings attached. The Bipartisan Infrastructure Law directed billions to states for roads and bridges, but most goes to projects that meet specific eligibility criteria: bridges over certain sizes, roads carrying specific traffic volumes. A rough local road in a small town might not qualify, even if it's in terrible shape. That's part of why the statewide backlog keeps growing. The funding mechanisms reward big projects over small ones.

There's also a conflict between what roads need and what winters demand. Road salt is cheap and effective in the short term. Alternatives cost more money upfront. Permeable pavements require maintenance and education about how they work. Recycled asphalt saves money eventually but means accepting a slightly less predictable product at first. None of these solutions are frictionless, and all require someone to decide they're worth the cost.

The other unresolved piece is salt's environmental toll. New Jersey has set standards for what's acceptable in drinking water, but road salt doesn't respect municipal borders. Salt applied on a highway in one town seeps into aquifers that another town depends on. Some regions have banned or limited road salt on municipal roads, but state highways remain salted as heavily as ever. The conflict between road safety (which the public demands every winter) and drinking water safety (which the public also demands) hasn't been resolved. It's being managed through a patchwork of local rules and voluntary guidelines that leaves large areas unprotected.

What's Still Unresolved

Roads are expensive and fix themselves for no one. A road built well lasts longer but costs more upfront. A road that's deferred and deferred eventually fails catastrophically, which costs much more and happens when least expected. Choosing between preventive work and emergency repair looks obvious from outside, but in a town that has to choose between fixing roads and funding schools, the pressure to choose schools is constant. State sets priorities, but local governments execute the work with local money. That gap between what's needed and what gets funded is why the pothole campaign happens every March, why New Jersey's infrastructure keeps pulling a D+, and why nearly a fifth of the state's roads remain in poor or fair shape.

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