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Road safety

Driving down the South Eastern Freeway needs additional road safety awareness, decision-making and actions. This is especially true for truck and bus drivers.

The last 7 km of the South Eastern Freeway comprises a very long and steep descent. The gradient becomes less severe near the bottom of the freeway. However, it becomes steeper as it continues downhill through a major, signalised intersection and into an urban area.

Truck and bus drivers should plan their travel down the South Eastern Freeway in advance. This is to ensure they are familiar with the road and the safe driving requirements.

Heavy vehicles pose more risk to other road users due to their mass and rigidity. Due to their momentum and mass, heavy vehicles take much longer to stop than lighter vehicles. These, together with speed, increases both:

  • the risk of the vehicle being involved in a crash
  • the severity of the crash.

How to descend safely

Trucks and buses can descend safely if drivers:

  • use the right safety techniques from the start of the descent at Crafers
  • follow signs and traffic controls.

When descending the South Eastern Freeway, truck and bus drivers must:

  • use low gear and appropriate engine braking
  • reduce speed to a maximum 60 km/h, unless otherwise signed at a lower speed
  • stay in the left lane between Crafers and Measdays Bridge.

Watch the video to help you prepare for driving down the South Eastern Freeway down-track.

Use low gear and appropriate engine braking

Truck and bus drivers must both:

  • use low gear and the appropriate engine brake before the Crafers Interchange
  • remain in this gear to the bottom of the South Eastern Freeway.

When they control their speed this way, they should not need to use their primary or foot brake, except for briefly to change gears.

In automatic trucks, lock the low gear in or switch to manual.

The law requires truck and bus drivers to:

  • use a gear that is low enough to enable the vehicle to be driven safely
  • not rely on the primary brake as the only way to slow the speed of the vehicle on the descent.

Primary or foot brakes can easily overheat and lose their effectiveness. When this happens, drivers could lose control of their truck or bus.

However, the intent of the low gear offence is not to completely prohibit the use of the primary brake. Drivers should use the primary brake if it is necessary in the circumstances.

Reduce speed

Trucks and buses must slow down to no more than 60 km/h from Crafers interchange to the bottom of the South Eastern Freeway. If there are signs showing a lower speed limit, they should follow the lower limit.

60 km/h is the maximum speed a truck or bus can travel on the South Eastern Freeway down-track. The appropriate speed for specific vehicles may be lower, such as for a heavy-laden truck.

To maintain safe travel, speeds may be further reduced below 60 km/h at any time via:

  • the variable speed limit signs
  • other temporary speed limit signs.

A further reduced speed limit may be due to inclement weather, reduced visibility or an incident, such as a crash or roadworks.

Stay in the left lane

Trucks and buses must stay in the left lane between Crafers and the Measdays Bridge exit ramp. They cannot overtake between these points.

However, trucks and buses may overtake on the descent as long as they both:

  • remain in low gear
  • do not exceed 60 km/h.

Safety ramps

Safety ramp

Use a safety ramp if you lose control, or have doubts about arriving at the major intersection safely.

Trucks and buses are encouraged to use safety ramps when they need to.

We don't charge trucks or buses a fee for using the safety ramps. We even cover the costs of towing heavy vehicles out of the safety ramp.

There are two signed safety ramps on the left side of the South Eastern Freeway between Crafers and Adelaide.

The safety ramps are located at both (see map below):

  • just before the entrance to the Heysen Tunnels
  • just past the Mt Osmond Interchange.

While the road flattens out on the approach to the second and last safety ramp, it then falls away again. The temporary flatter section of road may lead drivers to incorrectly think they will be able to regain control of their speed.

Truck or bus drivers who are not in full control of their vehicle must not try to “ride it out” to the major intersection at the bottom of the hill. Otherwise, they will risk serious injury or death to themselves and other road users.

Map illustrating safety information for drivers descending the South Eastern Freeway from Mount Osmond towards Adelaide. The route is highlighted in red, starting near Glen Osmond and continuing down a long, steep 7km descent that ends at a major intersection. A prominent warning sign advises "VERY LONG STEEP DESCENT (7KM) ENDS AT MAJOR INTERSECTION." Specific instructions for trucks and buses are listed: "Reduce speed," "Use low gear," and "Use left lane between Crafers and the Measdays Bridge (no overtaking)." The location of a "SAFETY RAMP" is indicated with a dashed line and text explaining, "If control is lost, use a safety ramp. There is no cost." Fixed camera locations are marked with camera icons along the route. Key locations labeled include Glen Osmond, Highgate, Springfield, Leawood Gardens, Mount Osmond, Heysen Tunnels, Measdays Bridge, Crafers, and Crafers West. Major roads intersecting or connected to the freeway are also shown, such as Glen Osmond Road, Cross Road, Fullarton Road, Portrush Road, Mount Lofty Summit Road, Piccadilly Road, and Charlick Road. The speed limit in one section is shown as 60 km/h. A compass rose indicates North. The map emphasizes the importance of safe driving practices on this downhill stretch of the South Eastern Freeway.

How to use a safety ramp

Safety ramps are very effective in safely stopping a speeding truck or bus. They are the best and safest option for all road users if the truck or bus driver has lost control.

There are clear signs marking the distance to the safety ramps to allow the driver plenty of time to prepare. Clear pavement markings are also in place to show which lane to use.

The main stopping force in a safety ramp is the drag caused as the vehicle sinks gently into a bed of gravel. The effect on the driver is less than the use of emergency braking, so the stopping force of the gravel:

  • should not result in injury to the driver
  • is unlikely to cause damage to the vehicle.

Removing a vehicle from the safety ramp

We need to use tow trucks to remove a vehicle from a safety ramp. However, we do not charge a fee to remove trucks and buses from a safety ramp or for ramp remediation.

Drivers must contact us with the emergency phone at the safety ramp. They can also phone the Traffic Management Centre on 1800 018 313.

More information

Companies and drivers should ensure:

  1. drivers have completed appropriate training
  2. drivers have a thorough understanding about safe driving on steep descents
  3. the truck or bus is roadworthy
  4. the brakes and engine brake are functioning properly.

The maximum speed limit for all other vehicles is 90 km/h, unless otherwise signed. Drivers should always drive according to the prevailing road conditions.

Advisory signs

Road sign - long steep descent ahead

Fixed signs can be seen in the lead up to the South Eastern Freeway down-track to alert drivers about the upcoming descent. They provide directions to drivers on descending safely and show where the safety ramps are.

These advisory signs, as well as speed limit and low gear signs, apply to drivers of trucks and buses. Find information about the definitions of a truck and bus.

Significant penalties apply for truck and bus drivers who do not follow the safe descent laws. Find information about applicable offences and penalties.

Heavy vehicle inspections

We maintain heavy vehicle checking stations or weighbridges across South Australia on key interstate networks. This includes Monteith on the Princes Highway, between Murray Bridge and Tailem Bend.

These facilities are licensed to the National Heavy Vehicle Regulator (NHVR) to undertake heavy vehicle compliance activities. This is in line with the Heavy Vehicle National Law (South Australia) Act 2013 and other specific state laws.

While other agencies also share these sites, they are mainly used by the NHVR and SA Police to conduct off-road intercepts and inspections. This is part of ensuring safe heavy vehicle operation and compliance.

When the variable signs show that 'Trucks and buses must enter', trucks with a Gross Vehicle Mass (GVM) greater than 4.5 tonnes and buses must enter these sites. Failing to enter the checking station when directed or disobeying the sign may result in a fine.

To help drivers to prepare to enter, variable signs are situated:

  • 400 metres before the checking station
  • just before the station.

All motorists should be aware that the posted speed limit will be decreased to 80 km/h when the checking station is open and enforced.

Monteith checking station

Checking Station

The Monteith site has two checking stations or weighbridges on either side of the Princes Highway. NHVR and SA Police use these facilities to intercept and inspect heavy vehicles travelling into and out of Adelaide, mainly via the South Eastern Freeway.

This site is used to conduct a broad range of heavy vehicle safety and regulatory activities, including:

  • roadworthiness and vehicle standards inspections
  • mass and dimensional limits compliance
  • compliance with heavy vehicle driver fatigue and related work/rest requirements
  • ensuring safe vehicle loading and suitable load restraint
  • registration and driver licensing checks.

The Monteith weighbridge has a five-plate weighbridge which can weigh large combinations in a single weigh. For example, B Double combinations.

Over-height vehicles

The height clearance for the Heysen Tunnels is 5.3 metres. This is also the clearance height for the Mt Osmond and Crafers interchanges.

Over-height warning signs are located before both approaches to the Heysen Tunnels.

A laser beam height detector checks the height of vehicles going towards the Heysen Tunnels. If the vehicle is too high to travel through the Tunnels safely, the over-height warning sign will flash. The flash directs the driver to stop in the stopping lane on the left of the road.

The laser beam height detector also automatically sends us an alert. Cameras are used to confirm the presence of an over-height vehicle. When confirmed, we will request police or emergency services to help the driver to turn the vehicle around through a dedicated break in the median strip.

Drivers may also contact us by using:

  • the emergency phones located near the Heysen Tunnels
  • their own phone to call the Traffic Management Centre on 1800 018 313.
Heysen Tunnels facts

Each tunnel:

  • is 480 metres long
  • is 10.5 metres wide
  • has three lanes, each lane 3.5 metres wide
  • has a height clearance of 5.3 metres
  • is equipped with emergency phones
  • has broadcast radio and mobile phone coverage
  • is connected by three emergency cross passages to the other tunnel.

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