Narrow lanes

Research shows that narrow lanes can have both positive and negative effects on road safety. The effect of a narrow lane on crashes often concerns only the number of crashes or total crash reduction. A distinction between crash types is rarely found. Some studies indicate that narrow lanes lead to a higher number of crashes while other studies reveal an opposite effect. The difference depends on the circumstances and factors like annual average daily traffic (AADT), road type, shoulder width and the percentage of heavy good vehicles (HGV). Most of the studies involve Crash Prediction Models (CPMs).