English 
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Russian During peak hours, recurrent congestion has become a structural challenge in most large cities. From fixed Variable Message Signs (VMS) to mobile-based, real-time navigation services, traffic guidance has long been considered a key instrument for congestion mitigation.
However, an essential question remains:
Can navigation and route guidance meaningfully relieve congestion caused by routine commuting demand at peak-hour bottlenecks?
Below are several observations and reflections for discussion.
1. Do “Red” and “Green” Roads on Digital Maps Mean the Same Thing?
The fundamental logic behind traffic guidance is straightforward:
If not all roads are congested during peak hours, redistributing traffic from congested links to less congested ones should theoretically balance network flow.
However, this assumption depends heavily on how congestion is defined.
On mainstream navigation platforms, traffic colors typically represent the ratio between current operating conditions (speed or travel time) and free-flow conditions. As a result, the same red color can indicate very different absolute speeds on different road types.
For example, an urban expressway operating at 40 km/h may appear “red,” while an adjacent arterial road operating at 30 km/h may still appear “green” due to its lower design speed and signalized intersections. In practice, despite appearing congested, the expressway may still offer a shorter travel time than the seemingly uncongested alternative.
2. Does Detouring to a “Less Congested” Road Always Save Time?
Traffic guidance often suggests “detouring slightly to save time,” but the effectiveness of such detours depends on the scale of the deviation and the structure of the road network.
In many cities with limited network redundancy, detouring between parallel expressways or ring roads often results in substantial additional distance. Even if an outer ring road remains uncongested, the extra travel distance required to exit, detour, and re-enter the original corridor frequently offsets any speed advantage.
Under typical urban network conditions, meaningful time savings through large-scale detours are relatively rare.
3. Are Commuters Unaware of Shorter Routes?
Traditional traffic assignment models assume that travelers are aware of network conditions and tend to select the shortest or fastest routes. While this assumption is imperfect, it largely reflects commuter behavior.
For daily commuters, congestion is a repeated experience. Most drivers will actively test alternative routes over time. If they ultimately continue using congested corridors, it is often because there are no significantly better alternatives.
Empirical analyses based on large-scale trajectory data consistently show strong route concentration for identical origin–destination pairs. Even when multiple routes are chosen, the travel time differences among the top alternatives are usually marginal.
4. If Navigation Can Relieve Congestion, Why Are Ride-Hailing Trips Still Congested?
Ride-hailing drivers almost universally rely on navigation systems. If route guidance could systematically bypass congestion during peak hours, ride-hailing trips should experience noticeably smoother travel conditions.
In reality, this is rarely the case. Even with mandatory navigation, ride-hailing vehicles remain subject to peak-hour congestion. This suggests that when all viable shortest paths are congested, navigation has limited room to optimize.
If congestion cannot be avoided even when navigation usage is near-universal, it becomes even more challenging to expect large-scale congestion relief among private commuters who may not consistently use navigation.
5. Does This Mean Navigation Is Ineffective?
Absolutely not. Navigation systems provide substantial value for:
- Non-commuting trips
- Unfamiliar destinations
- Tourists and occasional travelers
However, for routine commuting during peak hours, navigation alone may have limited ability to alleviate structural congestion. When all shortest paths traverse bottlenecks, guidance can optimize route choice but cannot eliminate congestion itself.
There is still potential for incremental improvement, as not all travelers choose optimal routes. Yet whether such optimization can produce network-level congestion relief remains uncertain.
From a system-wide perspective, only highly coordinated, centralized traffic control—or potentially fully autonomous vehicle ecosystems—may achieve true traffic equilibrium.
6. When Is Navigation Most Effective for Congestion Mitigation?
While navigation may have a limited impact on recurrent peak-hour congestion, it is highly effective in non-recurrent congestion scenarios, such as:
- Traffic accidents
- Road works
- Temporary closures
- Large-scale events
In these cases, real-time navigation can rapidly divert traffic away from affected areas, significantly reducing localized congestion and secondary delays.
There is no definitive answer to whether navigation alone can resolve peak-hour congestion. Under current urban road network conditions and prevailing commuting behaviors, its ability to alleviate recurrent congestion appears inherently limited. Nevertheless, navigation remains a fundamental component of modern urban mobility, particularly in managing non-recurrent disruptions, where timely guidance can significantly improve network performance.
