The importance of road drainage

As we know water is the most important compound ensuring life on this planet; But on paved roads the presence of water is usually trouble and can be very dangerous.  One of the main causes of road damage, longevity and serviceability of road systems, is presence of excess water filling the pores of road materials.  It is known that road structures perform better in dry conditions, because of this roads historically have been built on dry terrain.  On occasions where roads have had to be built on wet terrain, drainage structures have been designed to keep the road structures as dry as possible.

The first roads in Europe were built about 3,500 years ago.  Already at that time engineers designed the road structures to account for the importance of drainage.  They paid attention to cross-fall (helping water to flow to the lateral ditches), grade line (the road surface should be above the groundwater table and the surrounding ground) and lateral ditches (to convey water away from the road structure and prevent water table rise).

Poor drainage creates many problems for both users and road owners.  Typically these are:

1) Traffic safety (hydroplaning and ice), poor drainage is a safety issue.  Water may accumulate on the road like it does in ponds. Any accumulated water creates a risk of hydroplaning when the roads have rain on them.  A wet road surface reduces friction which leads to longer distances needed to brake vehicles.  Surface water can freeze during the night which can create an ice covered road. When this happens roads may become very slippery and hard to drive vehicles on.

2) Uncontrolled water flows and Culverts on roads can cause erosion.  Small diameter and clogged culverts can cause water to flow towards the road and produce erosion.  Water exiting from culverts can similarly cause erosion when it discharges directly on to erosive soil.  The sensitive soil types for erosion are silt, silty moraine and sand.  Vegetation can actually reduce erosion.

3) Reduced bearing capacity in the sub grade and road structures causing permanent deformation.  Poor drainage and moisture is a main contributor to permanent deformation on roads.  The earlier road projects in the United States have shown that in the Northern Climates permanent deformation is the main cause of undesirable rutting on low travel volume roads.  This can result in reduced traffic safety, increased driver health issues, lowed bearing capacities, and higher costs for road owners and users.

4) Differential frost heaves tend to exhibit poor drainage when the road is not maintained as it should be.  Frost heaves themselves cause unevenness and cracking on road systems.

5) Reduced pavement life time and increased pavement management costs.  The most important factor triggering the need for paving is poor quality drainage.

By improving the drainage conditions during construction and in critical sections of road systems; By maintaining these road systems it will increase the pavement lifetime by 1 ½- 2 times the life span of an unmaintained road.  The conclusion is that if drainage maintenance and  preventative maintenance is done properly it can lead to major savings for owners of roads and parking lots. Saving time and money by annual maintenance costs for paved road systems benefits everyone who comes in contact with these paved roads.

Parking Lots – Fall Prevention

Do parking lots pose special hazards?

Parking lots are a special adjunct to many workplaces. Even though you may not be conducting your job there (unless you are a parking attendant or maintenance worker), there is still a possibility that you can be injured. Besides the risk of violence, the major risk includes falls resulting from slips and trips.

Workplaces can help reduce slip, trip, and fall injuries by  having parking lots inspected on a regular basis and any defects repaired.


What factors contribute to fall incidents on a parking lot?

A smooth, even, flat surface is ideal for walking because it reduces the likelihood of twisted ankles or loss of balance which can lead to falls and other painful mishaps.

However, heavy use by both pedestrians, vehicle traffic and the elements cause a parking surface to deteriorate.

Leaks and spills of engine oil or antifreeze, which commonly occur wherever cars are parked, can further add to risks of slips and falls.

In outdoor parking lots, severe weather conditions damage to the parking surface. As a consequence the risk for falls due to slips and trips is relatively high in this environment.


Are speed bumps a fall hazard?

Speed bumps and tire stops are usually not necessary in a well-designed parking lot. Besides potentially causing damage to vehicles, they create a yet another hazard for tripping.

The layout of the parking area should make it impossible to drive unsafely or fast.

Otherwise, if speed bumps or tire stops are absolutely necessary:

  • Locate them away from pedestrian traffic (such as at entrance and exit areas).
  • Use a speed bump sign and post the recommended speed wherever such bumps have to be used. Speed bumps should be painted a color that will stand out.
  • Speed bumps should be designed according to the provisions of American National Standards Institute (ANSI) or Institute of Transportation Engineers (ITE) standards.

Are tire stops hazardous?

Tire stops are serious tripping hazards particularly when parking slots are occupied. When tire stops are present, a few precautions are advised:

  • They should no wider than the width of the vehicle.
  • They should be marked with a contrasting colour.
  • Special attention should be paid to their regular maintenance because they deteriorate faster than other elements of the parking area.

How can you prevent falls?

Falls can be prevented through a number of steps:

  • Good lighting.
  • Good housekeeping.
  • Good quality walking surface in the parking area.
  • Clear marking of steps, ramps, tire stops, speed bumps, or other elevation changes.
  • Garbage cans available for trash.
  • Sand/salt, shovels, or brooms available to clear the area.
  • Removal of debris from drains and grates to reduce flooding.
  • Appropriate walking pace: walk, don’t run.
  • Paying attention to where you are going.
  • Selection of proper footwear.

What does good housekeeping mean in terms of parking lots?

Good housekeeping includes:

  • Repairing any damage as soon as possible.
  • Posting warning signs or barriers when needed.
  • Cleaning all spills and oily spots immediately.
  • Marking oily or icy spots and wet areas.

Clearing ice or snow as soon as possible.

  • Removing clutter, debris and any obstacles from walkways.
  • Keeping the lighting system in good repair.


What responsibilities do workers have?

Safety is everybody’s duty, so workers as much as employers should:

  • Be aware when walking through a parking lot – watch for cars as well as fall hazards.
  • Never assume that the driver will see you first.
  • Clean or report spills right away.
  • Clear away clutter and debris, if they can.
  • Wear appropriate footwear for the situation (e.g., non-slip footwear in the winter).
  • Report hazardous conditions to their supervisors.
  • Remain aware that falls can happen anywhere, anytime.