Guides/Theory test
What Is a Contra-Flow Bus Lane? Who Can Use It and the Sign
Updated 22 September 2026 · 3 min read
A contra-flow bus lane is a bus lane that runs in the opposite direction to the traffic beside it. On a one-way street, it lets buses travel the "wrong" way while everything else goes with the flow. Only buses on a scheduled service may use it, and unlike a with-flow bus lane, taxis and cyclists may not.
With-flow and contra-flow: the difference that matters
| With-flow bus lane | Contra-flow bus lane | |
|---|---|---|
| Direction | Same as the traffic beside it | Opposite to the traffic beside it |
| Who may use it | Buses, taxis and cyclists during the hours on the plate | Only buses on a scheduled service |
| When it applies | The hours on the information plate; outside them, any vehicle | At all times, day or night |
| Stopping or parking | Not during the hours in force | Never |
Why the rules are stricter
A car that strays into a with-flow bus lane is in the wrong lane. A car that strays into a contra-flow lane is driving head-on at a bus. That is why there are no operating hours on a contra-flow lane and no exceptions for taxis or bikes: the lane is live whenever a bus might be coming the other way, which is always. It is also why the parking question is absolute. You must not stop or park in a contra-flow bus lane at any time.
Where you will meet one
Mostly in city centres on one-way systems, where a bus route needs to go against the one-way flow to keep its stops. Dublin city centre has several on its one-way streets, and you will meet them in the other cities wherever a one-way loop crosses a bus route. The sign is a blue panel with two arrows: a plain white arrow for you, and a bus symbol with an arrow pointing the opposite way. A variant shows the bus lane on the right of the carriageway.
How the theory test asks about it
Three ways. The sign question ("What does this sign mean?" with the blue two-arrow panel), the rule question "What traffic may use a contra-flow bus lane?" where the answer is scheduled buses only, and in the truck and bus bank "When is it legal to park in a contra-flow bus lane?" where the answer is never. The common trap is picking the with-flow answer that includes taxis and cyclists.
See the question
The official question on who may use a contra-flow bus lane, with the RSA explanation.
What traffic may use a contra-flow bus lane?Bus lane signs come up more than once
Information signs, bus lanes and cycle tracks are their own topic in the car test. The mock exam puts 40 questions in front of you in the official 45-minute format so you find out which signs you still guess at.
Sit a free mock theory testFrequently asked questions
+Can taxis use a contra-flow bus lane?
No. Taxis and cyclists may use with-flow bus lanes during their hours, but a contra-flow lane is for buses on a scheduled service only.
+Can I drive in a contra-flow bus lane outside the hours on the plate?
There are no hours. A contra-flow bus lane applies at all times, day and night.
+Can I park in a contra-flow bus lane at night?
No. You must not stop or park in a contra-flow bus lane at any time. In a with-flow lane the ban applies during the hours in force.