Proposal 06
Reversible and dynamic lanes
Using the same carriageway differently according to time of day and flow.
The problem
Commuter corridors carry strongly unbalanced flows: in the morning the inbound stream is far heavier than the outbound one, in the evening the reverse. A fixed cross-section is always oversized in one direction and undersized in the other.
The intervention
Reversible lanes with variable-message signing, dynamic lanes reserved for public transport or high-occupancy vehicles at peak times, use of the hard shoulder on suitable stretches. Capacity is gained without widening the carriageway.
- Where it works
- Roads with strong directional imbalance, ring roads and access routes to industrial areas or regional centres.
- What to measure
- Flow by direction and by hour, median peak-time travel time, safety and accident record.
- Guiding rule
- Prior study: no increase in travel time and no overlap of flows. Verification afterwards with the Travel Time Index.
This describes a family of interventions: costs, feasibility and impacts must be assessed case by case with local surveys and a network model.