liikennekaistansa

Liikennekaistansa is a Finnish term used in traffic engineering to describe a bottleneck in the arrangement of traffic lanes, where the effective capacity of a lane or group of lanes is reduced, leading to slower speeds and queuing upstream. The concept is applied to analyze points in a road network where capacity is constrained, such as near merges, lane reductions, or construction zones.

The term is formed from liikenne (traffic) and kaista (lane) and is used in Finnish road planning, traffic management, and media reporting on congestion. It is not an official engineering standard, but it appears in discussions of road capacity and congestion points, especially on highways with merging sections or work zones.

Causes of liikennekaistansa include temporary or permanent lane reductions, bottlenecks created by merges and weaving sections, geometric constraints that narrow the cross-section, and incidents that disrupt normal flow. The resulting effects are higher vehicle density, longer queues, and increased travel times, particularly during peak periods or in adverse conditions.

Assessment and mitigation: engineers study bottlenecks with capacity analyses and traffic flow models, using metrics such as throughput, density, and average delay. Mitigation measures include lane widening or redesign, improved merge geometry, ramp metering, dynamic speed limits, and carefully scheduled lane closures to minimize disruption.

See also: traffic bottleneck, lane management, road capacity analysis, overtaking lane (ohituskaista).