Q. What makes a pothole?
A: Potholes are created when moisture seeps into the pavement, freezes, expands and then thaws.

This repeated freezing and thawing weakens the pavement.

When this weakened surface is pummeled by traffic, small pieces will break off. At first, they are small pieces, but on a road with a lot of traffic, a pothole can form in a matter of hours.

This graphic illustrates how potholes form.

Q. Why do so many potholes occur in the Spring?
A: Spring temperatures warm the cold pavement, melting and evaporating any ice. This creates air pockets that can eventually cause the pavement to break up. A winter of heavy snow or rain and several freeze-thaw cycles can mean a big pothole season ahead.
Q. How are potholes repaired?
A: Since potholes vary greatly in size and conditions, DelDOT uses many different methods to repair the potholes. Crews use a material called cold patch, which is asphalt that can be used in lower temperatures and even in the rain. Actually, cold patch earned that name not because it can be used in lower temperatures, but because of the relatively low temperatures needed to produce the material.

Cold patch is used because through its chemistry, it actually remains pliable over time, whereas regular hot-mix hardens over time. Our crews use cold patch throughout the year, when we need to fill holes temporarily until a more permanent patch can be placed.
Q. Will some road repairs take longer to fix than others? If so, which road repairs take priority?
A: Yes. Locations that would take priority would be those that present a safety concern and are often areas of high traffic volume or speed, but we still review/address locations that may not meet these criteria.
Q. How much does it cost to fix all of these potholes?
A: In Fiscal Year 2010, it cost $2.2 million to repair the state's potholes.

So far this year, it has cost $0.9 million this year.

Overall, DelDOT's pavement management program considers typical deterioration rates which would account for the harsh winters. By using open-ended contracts, it gives DelDOT the flexibility to have major problems resolved quickly.

For background: DelDOT's budget and the "State budget" are not the same thing. DelDOT's Transportation Trust Fund is separate from the state General Fund. But both are certainly impacted. Similar to snow removal, when there is a need for a repair we fix it. Leaving a problem to get worse, or allowing something to deteriorate to a point that a road surface is unusable, is not how DelDOT operates.
Q. Are there any federal funds that are used for pothole repairs?
A: Not typically, federal funds are restricted and can only be used on federally eligible roads. Likewise, they can only be used primarily on capital improvements not operating expenses (such as cold patch).
Q. Who can I call to report a pothole?
A: If you encounter a pothole on a state-maintained road, there are many different ways you can report the problem:
  • You may go online here
  • You can also call 302.760.2080, or 800.652.5600 to report any road maintenance issues
  • You can email DelDOT at dotpr@state.de.us
Crews will rapidly investigate each report and will schedule repairs according to the severity of the pothole and according to the available resources.

If the pothole is on a street that is maintained by a town or city, call the public works or city manager's office in that location. However, some city streets are maintained by DelDOT. If you are unsure, you may call DelDOT at 760.2080.
Q. You filled a pothole, but a few days later it came back. Why don't the repairs last longer?
A: There are several reasons why a newly filled pothole may reopen:
  1. When conditions are cold or wet, the material used to patch potholes doesn't stick as well to the surrounding pavement as when conditions are dry and warm
  2. During the winter months, asphalt plants are closed and hot asphalt is not available until the spring. In the meantime, we will typically use a material called "cold mix" which isn't always as durable
  3. If the cause of the pothole is not corrected, such as water getting under the pavement, pothole patches may fail, or more potholes may form. The long-term solution is to repair and repave the road
Ultimately, our goal is safety and we must repair potholes as soon as possible.
Q. Do some roads have more potholes than others?
A: Yes. Roads with high traffic volumes have more potholes because of the amount of use. Bridges and ramps, which receive heavy doses of snow-removal chemicals in the winter, are more prone to potholes.
Q. Can anything be done to prevent potholes?
A: Yes. A good practice of maintaining and replacing roads will result in fewer potholes. DelDOT works hard to keep the roads in good condition, which minimizes problems like potholes.

However, they can never be entirely eliminated through good planning alone.

To fight these problems, roads today are built to reduce their moisture capacity, and researchers are working to develop better, more durable pavement materials and designs.

In addition, the cold patch mixtures have made dramatic improvements in their reliability.


Q. What is Microsurfacing?
A: Microsurfacing is a thin, tough layer of asphalt emulsion containing aggregate (rocks), water and mineral fillers. It is used to seal cracks and prevent moisture from penetrating the road base. Typically, half of a road is closed at a time for microsurfacing. The length of time the road is closed depends on air temperature and humidity and whether one or two passes of microsurfacing is applied.
Q. Why are you doing this work when the road appears to be in fine condition?
A: This is the ideal time to apply microsurfacing. This process is often most effective when the existing hot-mix surface is 5-7 years old and showing only minimal signs of distress. If the roadway does exhibit signs of distress, we must first patch and crack-seal the major problems, prior to applying the microsurface.
Q. Why are you using microsurfacing instead of just re-paving the roads?
A: Microsurfacing provides a smoother road surface and less loose material than traditional surface treatment, such as tar and chip. It is primarily used for preservation of existing hot-mix roadways, which is important as transportation officials look for cost-effective ways to stretch their pavement funding.
Q. Why does it seem rougher on my road after you did this work?
A: When a road is first microsurfaced, it may present an initially rougher driving surface. This somewhat abrasive surface creates a more skid-resistant surface, thus increasing the safety of the road itself. However, as cars travel over the road, the stones and materials become compressed and smoother, ultimately resulting in a road surface that is nearly as smooth as traditional asphalt hot-mix overlay, but still course enough to improve skid resistance.
Q. Are the nearby residents notified before microsurfacing is performed?
A: Yes. As part of the agreement with DelDOT, the contractor doing the work is obligated to give affected residents at least 48 hours notice of nearby micro-surfacing. The contractor will often hang a note on the doorknob of nearby homes. In addition, DelDOT issues press releases detailing where and when the micro-surfacing will occur. To view these press releases, go to www.deldot.gov
Below is the text from a door hanger used to notify resident of a recent project:

As a reminder, between the hours of 8 AM and 5 PM, (weather permitting), your road will be given a new surface. It is called Microsurfacing - a thin, tough layer of asphalt emulsion containing aggregate (rocks), water and mineral fillers. It is used to seal cracks and prevent moisture from penetrating the road base.

This application will stick to vehicles, shoes, and clothing. Please DO NOT drive on it with your car, walk on it, or ride your bicycle on it until the surface is completely dry. It takes about an hour to dry, depending on air temperature and humidity. Also, please DO NOT use your lawn sprinkler during this process.

The contractor (name and address here) will be closing one side of the road, at the time, with flaggers to direct traffic. Emergency vehicles will have access at any time. Local residences need to be aware of the possibility of a one-hour delay and plan accordingly.

The Delaware Department of Transportation and the contractor would like to thank you for your cooperation.

If you have any further questions please call the Delaware Department of Transportation, Public Relations Office at 800.652.5600 or 302.760.2080.