Transport competitiveness depends on its fixity

The physical characteristics of both private and public transport services – the path it travels, the obstacles it face – matter a lot in determining public transport’s competitiveness as a mode choice, as all participants in a transportation network self-adjust their routes, times and modes.


Law of Triple Convergence explains the competitive nature of both public and private transport modes within a transportation network: trip makers would shift to the other mode, when options of changing route and time become restrictive (e.g. bus users, tired of infrequent schedule and time-consuming route, will switch to cars)

Public transport’s mode share increase correlates with either increase in its competitiveness or decrease in private transport’s competitiveness. Competitiveness of public transportation depends on its network’s ‘fixity’ vis-à-vis private transportation in providing the most direct, reliable and efficient path.

Auto-oriented cities tend to possess less-competitive public transport network due to the proliferation of newer highway-oriented travel patterns not served by fast-obsolete public transport routes.

Thus, a competitive public transport network must consider routing efficiency from the private vehicle travel pattern’s perspective, and minimize private-public transport’s route efficiency gap.



Comparison between two metropolitan transportation networks with low (top) and high (bottom) public transport accessibility competitiveness vis-à-vis private transport

Transport network fixity

Bus route fixity problem arises with free-flowing roads that widen the door-to-door travel time gap between car users and bus users. Constrained by fixed travel time budget, most people would prefer the private vehicle mode which offers quicker trip.


Comparisons between less competitive (left) and more competitive (right) bus routes, in which the less competitive route has to cover substantially longer distances despite covering the exact same catchment volume due to the bus route fixity problem

Limited access roads and gated developments complicate bus and pedestrian routings. Free-flowing slip roads and complex highway interchanges make simple bus-to-bus (or rail-to-bus) transfers less efficient.

To solve the bus route fixity problem, the road network needs to accommodate flexible and simplified routing for buses and pedestrians.


Road network rigidity forces awkward configuration of connection or transfer across two public transport routes, and coupled with piece-meal rapid transit station placement strategy, renders the lower-order bus network totally detached from the higher-order rapid transit network