Traffic rules, road signs and road markings
Traffic Rules and Driving Law in Singapore
Singapore traffic law rests on a few organising ideas that question setters return to repeatedly. Vehicles keep to the left; on a multi-lane road you use the leftmost lane that suits your direction, and you overtake on the right. On expressways the rightmost lane is for overtaking, not cruising. Default limits are 50 km/h on ordinary roads and 90 km/h on expressways unless a sign says otherwise, with lower signed limits in school zones and some residential areas.
Signals: green means proceed if the way is clear - it is not an absolute right of way. Amber means stop unless you are so close that stopping would itself be unsafe. Red means stop behind the stop line. At a roundabout you give way to traffic already circulating, which approaches from your right. At a yellow box junction you may not enter unless your exit is clear. At a zebra crossing you must stop for any pedestrian waiting or crossing. Signal before every lane change or turn, and cancel afterwards.
Traps: treating green as 'go', forgetting to give way to oncoming traffic when turning across it, treating the right lane as a fast lane, and reading amber as 'speed up'. Another is shrinking the following gap in rain, when it should be doubled.
Rule of thumb: pick a fixed object ahead. At 50 km/h you should be at least two seconds behind the vehicle in front, four in the wet. If you cannot say 'one thousand and one, one thousand and two' before reaching it, you are too close.
Road Signs and Road Markings
Signs are examined by shape and colour before you read a single word. Red-bordered circles prohibit: no entry, no U-turn, speed limits, no parking. Blue circles command: turn left only, minimum speed, route for buses. Red triangles warn: bend, junction, pedestrian crossing, slippery road. Rectangles give information or direction. The red octagonal STOP sign is the only sign of its shape, and the inverted triangle means Give Way.
Markings carry equal weight. A continuous white line at the centre or lane edge means do not cross or change lanes; a broken white line may be crossed when it is safe and after signalling. Double yellow lines mean no parking at any time; a single yellow line means no parking during the hours stated on the plate. Double red lines mean no stopping at any time; a single red line means no stopping during stated hours. Yellow zig-zags mark school gates and pedestrian crossings - no stopping there at all. A yellow box junction must not be entered unless your exit is clear. Hatched chevrons and chevron islands are not driving space. Bus lane markings apply during the hours shown on the accompanying sign.
Traps: confusing 'no parking' with 'no stopping'; assuming a single yellow line is unrestricted all day; entering a yellow box because the light is green; and believing a broken line lets you change lanes without a mirror check and signal.
Rule of thumb: colour first - red forbids, blue commands, yellow restricts, white divides - then read the plate for hours and exceptions.