Closing Rue du Bailli to cars

What is being tested?

What happens to traffic if Rue du Bailli is closed to passenger cars while buses and taxis retain access? The simulation compares normal traffic with two possible extents: restricting only the section between Avenue Louise and Rue de Livourne, or extending the restriction along Rue du Bailli to the Parvis de la Trinité.

To answer this question, we ran a full-day microscopic mobility simulation for Wednesday 19 August 2026, from 00:00 to 23:59. Each scenario represents passenger traffic together with 1,498 scheduled STIB bus movements, allowing effects to be compared over the morning peak, daytime and evening peak.

The area of interest (AOI) is the footprint of the road network evaluated in the results. It was extracted around all restricted Rue du Bailli segments using a configured 0.8 km surrounding buffer. Complete road segments are retained when they cross the extraction boundary, so the resulting footprint extends beyond the nominal buffer. The map shows the same 904 evaluated road segments used by the traffic indicators and impact maps.

Two possible closure extents

The Livourne segment represents the short section from Avenue Louise to Rue de Livourne. The full Rue du Bailli option continues west through the Faider and Simonis intersections to Parvis de la Trinité. In both cases, passenger cars are excluded from the selected street segments while the modelled bus service retains access.

Comparing both extents with the same baseline answers a practical design question: does extending the car restriction across the whole corridor create substantially more traffic disruption than treating only the existing Louise–Livourne section?

How much does closing the street affect wider traffic?

Across the full day and the whole AOI, the Livourne segment has a small network-wide effect: average travel time and total delay both rise by 0.6%, average speed falls by 0.2%, and CO₂ emissions rise by 0.4% compared with the baseline.

The full Rue du Bailli restriction has the larger effect, although it remains modest at network scale. Average travel time rises by 1.8%, total delay by 3.1%, average speed falls by 0.6%, and CO₂ emissions rise by 1.1%. The 95th-percentile travel time changes little in either scenario, indicating that the main result is a small broad shift rather than a large deterioration for the longest journeys.

When is traffic pressure highest?

Results are reported in 15-minute intervals. The congested-road indicator measures the share of evaluated road length moving below half of its normal free-flow reference speed.

The largest increase for the Livourne segment occurs from 20:45 to 21:00, when 2.9% of evaluated road length is congested, 0.7 percentage points above baseline. The full-street restriction has its largest increase from 17:15 to 17:30, at 4.9%, or 1.2 points above baseline.

The broader intervention therefore has the clearer evening-peak effect, but neither scenario creates high congestion across most of the AOI at the same time.

Where does traffic slow down?

The maps below show road-speed changes during each scenario’s most disruptive interval. Red roads are slower than in the baseline; blue roads are faster. They show local redistribution that is hidden by the modest network-wide averages.

For the Livourne segment, the strongest slowdowns appear around Rue du Bailli and Avenue Louise, with effects also visible toward Rue Defacqz and around Rue d’Écosse, Rue Bosquet and Rue de l’Hôtel des Monnaies. During the full-street peak, slower conditions are more dispersed, including Avenue Louise, Boulevard de Waterloo, Avenue Ducpétiaux, Rue Saint-Bernard and Rue Washington.

These locations identify streets to monitor in a real circulation plan; the map does not imply that every red segment is caused only by cars leaving Rue du Bailli.

Impact on public transport

The public-transport analysis contains 1,498 scheduled bus movements on STIB lines 38, 50, 54, 59, 60, 71, 95 and 96. The same cohort is compared across all three scenarios.

Mean running time across all buses is effectively unchanged: 0.1 seconds faster with the Livourne restriction and 0.5 seconds slower with the full-street restriction. The largest matched line-direction changes are also limited. Line 96 toward Gare du Midi is about 7 seconds slower with the Livourne restriction, while line 96 toward Legrand is about 7 seconds slower with the full-street restriction. On line 54, which uses Rue du Bailli, mean changes remain within about three seconds.

The simulation includes buses but not tram 81, pedestrians or cyclists. It therefore measures traffic and bus operation, not the walking, cycling, public-space or tram benefits that could motivate the street project.

Checking the simulation against observed traffic

Thirteen traffic-counter locations fall inside the analysis area: three Brussels Mobility counters and ten Telraam cameras. Counter directions with a safe geometric match are linked to the corresponding directed edge in the simulation network; unmatched directions are explicitly flagged. Select a location on the map to compare its 15-minute simulated vehicle flow with observations for Wednesday 19 August 2026, where measurements are available.

Agreement in the timing and scale of the daily traffic profile increases confidence that the model represents existing conditions at that location. Differences identify where demand or routing needs further calibration. This is a local check at the available counters, not proof that every street in the AOI is reproduced accurately; the widget reports missing observations rather than filling the gaps.

What do the results mean for Rue du Bailli?

Within this simulation, closing the Louise–Livourne segment to cars has little effect on traffic across the wider area. Extending the restriction to Parvis de la Trinité produces more visible local redistribution and a larger evening-peak effect, but the full-day network changes remain modest and modeled bus performance is nearly unchanged.

The figures are comparative simulation results, not exact forecasts. All scenarios use the same demand source and allow 40% of vehicles to reconsider their route during the run. The full-street scenario ultimately contains 0.4% fewer requested trips than the baseline, so its network-wide totals should be interpreted with that difference in mind. Before implementation, the streets highlighted by the maps should be checked with observed counts, and the unmodelled effects on tram 81, walking, cycling, deliveries, local access and public space should be assessed separately.