"It is disturbing that the sensitivities of the cannabis and cocaine tests were all quite low, although further testing of the cocaine tests is desirable due to the low prevalences and the low concentrations encountered in this study. There are several countries in Central and Southern Europe for which these two substance classes are of special interest. On the other hand, it seems the sensitivities of the devices are generally better for amphetamines, a frequently encountered drug class among the DUI drivers in the Nordic countries. The suitability of the device for the intended national DUI population should also be considered, for example, PCP is rarely, if ever, found in Europe, therefore at the current time utilising a PCP test is unnecessary. Since the on-site tests are relatively expensive the suitability of all the individual substance tests incorporated in the device should be considered.
"The evaluation showed that none of the evaluated tests is on a desirable level (>80% for sensitivity, specificity and accuracy) for all of the separate tests that they comprised. However, there were tests that performed already on a promising level for one or more substance classes. The DrugTest 5000 had the best overall results. The next best device was Rapid STAT, which performed at a similar level, except for the cocaine test which was somewhat less sensitive. Clearly the best device in terms of sensitivity for amphetamines was the DrugWipe 5+."

"As with cannabis, alcohol use increased variability in lane position and headway (Casswell, 1979; Ramaekers et al., 2000; Smiley et al., 1981; Stein et al., 1983) but caused faster speeds (Casswell, 1977; Krueger & Vollrath, 2000; Peck et al., 1986; Smiley et al., 1987; Stein et al., 1983). Some studies also showed that alcohol use alone and in combination with cannabis affected visual search behavior (Lamers & Ramaekers, 2001; Moskowitz, Ziedman, & Sharma, 1976). Alcohol consumption combined with cannabis use also worsened driver performance relative to use of either substance alone. Lane position and headway variability were more exaggerated (Attwood et al., 1981; Ramaekers et al., 2000; Robbe, 1998) and speeds were faster (Peck et al., 1986).
"Both simulator and road studies showed that relative to alcohol use alone, participants who used cannabis alone or in combination with alcohol were more aware of their intoxication. Robbe (1998) found that participants who consumed 100 g/kg of cannabis rated their performance worse and the amount of effort required greater compared to those who consumed alcohol (0.05 BAC). Ramaekers et al. (2000) showed that cannabis use alone and in combination with alcohol consumption increased self-ratings of intoxication and decreased self-ratings of performance. Lamers and Ramaekers (2001) found that cannabis use alone (100 g/kg) and in combination with alcohol consumption resulted in lower ratings of alertness, greater perceptions of effort, and worse ratings of performance."