Quantifying collision potential in airport surface movement

• Both the frequency and the collision potential of interactions between aircraft on the airport surface can be quantified • Metrics based on the minimum time to a potential loss of separation correlated well with subjective occurrence severity • The interaction statistics show significant variations between airports and strong dependence on local congestion • Dependencies on interaction category and location were also explored • Treating “problematic” interactions as collision risk indicators overcomes the analytical difficulty of making predictions based on the rare occurrences of actual collisions • Future work will focus on identifying the factors that maximize the predictive value of historical “yield factors” • Identifying the causal factors will also help to predict the effect of Operational Improvements on these ratios and therefore on accident rates.