Speed and load limit

Speed and load limit

Speed limit is defined as the maximum speed at which a vehicle is legally permitted to travel, as within a specific area, on a certain road, or under given conditions. Roads of different categories and under different situtions are designed for designated design speeds at which vehicles can travel with convenience and safety. 

However, at certain locations, such as approaches to manned and unmanned level crossings, sharp curves, congested/accident-prone locations, residential streets, etc., control of speed may become necessary to promote orderly traffic movement and improved safety.

Speed management can be defined as a set of measures to limit the negative effects of excessive and inappropriate speeds. Not only does this mean measures to restrict speed, but it also includes elements of road design, separation of different types of road users, road markings etc. based on the volume and type of traffic on that particular road. One of the most important aspects of speed management is education of road users.
The advantages and disadvantages of higher speeds, and why speeds should be low in urban areas

Advantages
• Allows reduction of journey time
• Enhances mobility
• Caters to driver's adrenalin rush & entertainment (questionable advantage)

Disadvantages
• Increases the distance travelled before a driver's reaction time + stopping distance can stop a vehicle
• Increases fuel consumption
• Increases greenhouse gas emissions
• Lesser time for both driver and other road users to recognize

Hazards
• Reduced ability of other road users to judge vehicle speed and time before collision
• Lesser opportunity for other road users to avoid a collision
• Greater likelihood that a driver will lose vehicle control
• Adversely impacts quality of life of vulnerable road users

LOAD LIMIT

Load limit sign on the road indicates the load of the vehicle, which should ply on the road. Overloading has been recognized to be both a safety concern as well as a cost concern. Overloaded vehicles, especially freight vehicles, destroy roads and negatively impact economic growth. The damage caused grows exponentially as the load increases. Damage to roads as a result of overloading leads to higher
maintenance and repair costs and shortens the life of a road which in turn places an additional burden on the government as well as law-abiding road users who ultimately carry the costs of inconsiderate
overloading. 

If the problem of overloading is not controlled, this cost has to be carried by the road user, which will require significant increases in road user charges such as the fuel tax, vehicles license fees, and overloading fees. Overloading is a safety hazard that leads to unnecessary loss of life, and also the rapid
deterioration of our roads, resulting in increased maintenance and transportation costs.
Overloaded vehicles threaten road safety and are contribute to many of the fatal accidents on roads. The overloaded vehicle will not only put the driver at risk but also passengers and other road users.
The following are the risks of overloading vehicles:

• The vehicle will be less stable, difficult to steer and take longer to stop. 
• Vehicles react differently when the maximum weights which they are designed to carry are exceeded.
• Overloaded vehicles can cause the tyres to overheat and wear rapidly which increases the chance of premature, dangerous and expensive failure or blow-outs.
• The driver’s control and operating space in the overloaded vehicle are diminished, escalating the chances of an accident.
• The overloaded vehicle cannot accelerate as normal – making it difficult to overtake
• At night, the headlights of an overloaded vehicle will tilt up, blinding oncoming drivers to possible debris or obstructions on the roadway
• Brakes have to work harder due to ‘the riding of brakes’ and because the vehicle is heavier due to overloading. 
• Brakes overheat and lose their effectiveness to stop the car.
• Due to overloading of passenger vehicles, seat belts are often not used as the aim is to pack-in as many persons as possible into the vehicle
• The whole suspension system comes under stress and, over time, the weakest point can give way.
• By overloading your vehicle you will incur higher maintenance costs to the vehicle – tyres, brakes, shock absorbers and higher fuel consumptionInsurance cover on overloaded vehicles may be void as overloading is illegal
  

The following measures are suggested to counter overloading

• A strategy map that will assist planners in deciding on appropriate locations for additional weighbridges.
• A database containing information on weighbridge operations and monitoring, as well as monthly reports that will be accessible via a website.
• This database will also contain information on habitual offenders.
• Portable scales are in the process of being evaluated, determining their accuracy and acceptability for prosecution purposes. 
• Legislation to extend the responsibility of overloading to the consigner and the consignee is in the process of being drafted.
• Vehicle testing stations are equipped with state-of-the-art testing equipment such as break rollers to test the quality of a vehicle’s breaks, a scuff gauge to measure the wheel alignment and many others.  
• This is done to ensure that when a vehicle is certified as being roadworthy it will definitely meet the prescribed standards.
• The National Roads Agency can enter into performance-based agreements with the private sector for the operation and administration of the weighbridges, and service agreements with the Local Traffic Authorities in order to ensure a dedicated attack on overloading.
• The strategy includes the monitoring and weighing of vehicles attempting to bypass the weighbridges by using alternative routes.