SlopeUnited States

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14. Slope

A slope is a section of road that rises or descends noticeably. A steep slope can affect vehicle speed, braking distance, traction, visibility and the ability of heavy or low-powered vehicles to maintain a steady speed.

Warning signs may indicate a steep ascent or dangerous descent and may show the gradient as a percentage. Drivers should adjust their speed early, select a suitable gear and remain prepared for slow vehicles, bends and changing road conditions.

Steep-grade warning sign on eastbound Interstate 280 near Exit 8B. (West Orange, New Jersey, United States)
Wikimedia.org • Famartin • CC BY-SA
What is a road slope?

A road slope is a section of road that rises or descends over a particular distance. It may also be called a gradient, incline or decline.

How can you recognise a steep slope?

A steep slope may be indicated by a warning sign showing an ascending or descending road. The sign may also display the gradient as a percentage.

What does a gradient of 10% mean?

A gradient of 10% means that the road rises or falls approximately 10 metres for every 100 metres travelled horizontally. It does not mean that the road is inclined at 10 degrees.

What is the difference between an ascent and a descent?

An ascent rises in the direction of travel, while a descent falls in the direction of travel. The same section of road is therefore an ascent in one direction and a descent in the other.

Does a slope warning sign impose a speed limit?

Not normally. It warns of a hazard rather than setting a numerical limit. Drivers must still respect the applicable speed limit and reduce their speed further when necessary.

How should you approach a steep descent?

Reduce speed before the descent, select a suitable gear and maintain a safe following distance. Avoid allowing the vehicle to gain excessive speed.

Which gear should you use when descending?

Use a gear that provides sufficient engine braking and helps keep the vehicle at a controlled speed. The appropriate gear depends on the vehicle, gradient and road conditions.

Should you coast downhill in neutral?

No. Coasting reduces engine braking and may make it harder to control the vehicle’s speed. Keep the transmission engaged while descending.

Why should you avoid continuous heavy braking?

Continuous braking on a long descent can cause the brakes to become excessively hot and lose effectiveness. Select a suitable gear, control speed early and use the brakes progressively when needed.

What is brake fade?

Brake fade is a reduction in braking performance caused by excessive heat. It can occur when the brakes are used continuously during a long or steep descent.

How should you drive uphill?

Select a suitable gear before the engine begins to struggle and maintain a steady speed where possible. Be prepared for heavy or low-powered vehicles travelling slowly ahead.

May a vehicle lose speed on a steep ascent?

Yes. Heavy vehicles, vehicles towing trailers and low-powered vehicles may slow considerably. Other drivers should maintain a safe distance and avoid impatient manoeuvres.

May you overtake near the top of a slope?

Do not overtake when the crest prevents you from seeing far enough ahead. Overtaking near a hilltop may also be expressly prohibited by local law, signs or road markings.

Why is visibility limited near the crest of a slope?

The road surface itself may hide approaching traffic, stopped vehicles, pedestrians or other hazards beyond the crest.

Who has priority on a narrow slope?

Some countries give priority to uphill traffic, while others rely on signs or ordinary obstruction rules. Drivers must follow local law and cooperate when passing is difficult.

How should you meet another vehicle on a narrow slope?

Reduce speed and use a passing place where available. The driver who can reverse or move aside more safely should cooperate, subject to any applicable priority signs or local rules.

How do rain, snow or ice affect a slope?

They reduce traction and make acceleration, braking and steering more difficult. Increase the following distance, use smooth controls and reduce speed before entering the slope.

Why are cyclists vulnerable on slopes?

Cyclists may travel slowly and move less steadily when climbing, while they may reach high speeds when descending. Drivers should leave sufficient space and avoid overtaking without a clear view.

How should you park on a slope?

Use the parking brake, select the appropriate gear or parking position and follow local rules concerning wheel position. Make sure the vehicle cannot roll into traffic.

Can a slope affect towing?

Yes. A trailer increases the load on the engine and brakes and may affect stability. Drivers should use a suitable gear, maintain additional distance and avoid excessive speed.

1 United States 2 Motorway 3 Expressway 4 Speed limit 5 Minimum speed 6 Advisory speed 7 Bike path 8 Pedestrian warning 9 Tunnel 10 Bridge 11 Speed bump 12 Toll road 13 One-way traffic 14 Slope 15 Bus lane 16 Bus stop 17 Dead end 18 Stop sign 19 Give way 20 Roundabout 21 Road narrowing 22 Pedestrian crossing 23 Railway crossing 24 Mandatory direction 25 Turn prohibition 26 School area 27 Crossing animals 28 Slippery road 29 Rockfall 30 Aircraft 31 Curve 32 Chevron 33 Wrong-way driving 34 Roadworks 35 Height limit 36 Weight limit 37 Radar speed sign 38 Selective barriers 39 Traffic lights 40 Traffic lights warning 41 Pedestrian lights 42 Road markings 43 Bike box 44 Speed feedback 45 Driving licence 46 Traffic mirror 47 Emergency telephone 48 Cycling route 49 Parking 50 No parking 51 No stopping 52 Parallel parking 53 Park and ride 54 Kiss and ride 55 Disabled parking 56 Traffic management 57 Reversing 58 U-turn 59 Carpool 60 Detour 61 Uncontrolled crossroad 62 Ramp 63 Exit 64 Horse riding 65 Emergency exit 66 Runaway truck ramp 67 Oversize load 68 City limit 69 Tourist attraction 70 Horn 71 Axle weight limit 72 Licence plate 73 Charging station 74 Flooding 75 Dip 76 Horse 77 Local traffic 78 Pedestrian 79 Cyclist 80 Motorcycle 81 Truck 82 Bus 83 Police 84 Ambulance 85 Police signals 86 Gravel road 87 Pothole 88 Median strip 89 Public property 90 Path 91 Particulates 92 Air pollution 93 Interchange 94 Rush hour 95 Filling station 96 Road code 97 Two-way traffic 98 Passing lane 99 Street gutter 100 Road debris ...