Static Alternate-Direction Center-Running Transit Lanes

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Static Alternate-Direction Center-Running Transit Lanes are an application of center-running lanes for space-constrained settings, in which a single central transit lane changes direction mid-block and at intersections. Transit vehicles can use the lane to bypass queues at signalized intersections and merge back into the general traffic lane afterward, typically during a dedicated phase preceding the general-traffic through phase. It can also be described as a continuous center-running queue-jump lane (G1).

Key Facts

Stops
Stops are located on boarding islands, generally before the intersection, though they can be placed mid-block and in short segments where it’s possible to have separate lanes for each direction.
Left Turns
Left-turn conflicts are similar to those of standard center-running lanes. This conflict is normally managed via separate signal phases or with yields or stops in low-traffic settings with good lateral visibility.
Right Turns
N/A
Parking
They are protected from on-street parking encroachment by design, as they are located far away from the curb.
Enforcement
Similarly to standard center-running lanes, they can be enforced against lateral encroachment using physical separators, ranging from surmountable elements such as armadillos, plastic or bevelled concrete curbs, to non-surmountable hard separators and mineral or even landscaped medians. Cameras and physical traps can be used to prevent unauthorized vehicles from entering them at intersections.
Transit Signal Priority
Most TSP strategies can be effectively implemented, including active TSP, notably at multi-stage pedestrian crossings (shorter clearance times for anticipated green/truncated red).
Cost
Medium to very high, as it can be associated with major reconstruction of the entire roadway and reconfiguration of intersections, drainage or even utilities.

Use Cases

Static Alternate-Direction Center-Running Transit Lanes are a relatively recent solution in the transit priority toolbox. Notably, they have been systematically deployed in many BHNS (Bus à Haut Niveau de Service) projects in France, starting with the first extensive implementation on Rouen’s TEOL guided busway project in the early 2000s [1, 2, 3], to provide transit priority on narrow corridors. Another notable example is Lens-Béthune’s BHNS, in Northern France, where the central static alternate-direction lane spans almost 8 km with stops located on the curbs in mixed-traffic segments.

Bibliography

  1. Fin, B. et al. (ed. 2012). Buses with High Level of Service. Fundamental characteristics and recommendations for decision-making and research. Results from 35 European Cities. COST.
  2. CEREMA (2024). Les couloirs bus bidirectionnels à voie unique : optimiser le partage de la voirie. Édition | Insertion urbaine des transports collectifs de surface (IUTCS), fiche n° 12.
  3. CEREMA (2024). Urban insertion of surface public transport (IUTCS). Fact sheet no. 12, Bidirectional single-lane bus lanes: optimising road sharing.