Engineering judgment and road safety.

• Engineering judgment is widely trusted. In road safety the trust may not be deserved. • Engineers are not trained in road safety nor learn it from their own experience. • Engineers must hold safety paramount. Transportation engineers cannot really do so. • It is up to standard committees to strike and informed safety vs. 'utility' balance. Decisions that highway and traffic engineers make significantly affect the safety of road users. The documents that guide highway and traffic engineering practice suggest that many of these decisions be made by 'engineering judgment'. One would like this judgment to be informed by evidence-based anticipation of their likely safety consequences and by a professional ability to balance safety against mobility and other dimensions of 'utility'. I show that these desiderata are largely unfulfilled. The many implications of this finding are discussed. [ABSTRACT FROM AUTHOR]