Solid Line, Left-Turn Arrow and a Temporary 40 Sign at 22:40
You are driving a hired sedan on a three-lane urban dual carriageway in Abu Dhabi at 22:40. You intend to continue straight through the next signalised junction. Two hundred metres before it, an overhead sign shows that the left lane is left-turn only. Sixty metres before the junction you moved into the left lane to pass a slow bus, and the line on your right has just changed from broken to solid white. You then pass a yellow temporary sign reading 'ROAD WORKS - 40' mounted beside the permanent 80 km/h sign; no workers or plant are visible and the road surface is intact. Traffic is light, the road is dry, and a car behind is closing on you with its headlights flashing.
1. You are now inside the solid line and the overhead sign does not match your intended route. What are your legal and safe options?
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A solid white line is a do-not-cross marking: once it begins you must stay in the lane and accept whatever that lane does. The overhead sign is a regulatory mandatory-direction sign, so the left lane leads to a left turn only.
Your legal and safe option is therefore to complete the left turn and recover the route afterwards - a U-turn at the next junction, or a loop back through the service road network. Expect two to three minutes of delay; that is the cost of the earlier decision.
What you must not do is compound the error:
- do not stop in the lane to think about it;
- do not reverse back over the line;
- do not straddle the line to 'straighten out'.
All three are offences, and all three create a rear-end risk at 22:40 with a car closing fast behind you. The decision point was 60 m back, when the line was still broken.
2. Which speed limit applies through the works zone, and what does complying with it actually require of you in metres?
Read the worked answer
The 40 km/h sign applies. A temporary yellow works sign is a regulatory sign, not advice, and it overrides the permanent 80 limit while it is displayed. The absence of visible workers at 22:40 does not cancel it - surfaces, lane widths and plant positions can change overnight.
Compliance has a distance cost that drivers routinely misjudge. From 80 km/h (22.2 m/s) at a gentle 0.25 g you need roughly v²/(2a) = 493/4.9 ≈ 100 m to reach 40 km/h; even at a firmer 0.35 g you still need about 72 m. If you only react when you reach the sign, you will pass it well above 40 and be in breach.
So the correct action is to begin reducing speed 100-150 m before the sign and to be at or below 40 as you draw level with it. With a fast-closing car behind, brake earlier and more progressively rather than later and harder, and show the brake lights early so the driver behind reads your intention.