Police pursuit recording forms are clearly preferable to reliance on official police records, such as arrest activity reports, since these forms yield more systematic and detailed data. Because the forms do not eliminate all measurement difficulties and in view of acknowledge shortcomings of official police pursuit data, an alternative is suggested that involves police emergency band radio transmissions. Police emergency band radio transmissions are appealing as an alternative or supplemental data source for police vehicle pursuits because they avoid conventional biases, are immune to problems of retrospective editing since data are reported and recorded in process, and avoid the problem of recall because data are recorded as they occur. The major validity concern about police emergency radio transmissions as police pursuit data sources involves the issue of sampling or selectivity in police pursuits that are recorded on emergency radio bands. 24 references, 2 notes, and 3 tables