Final answer:
Increased vigilance for roadside bombs is necessary in areas with recent terrorist activities, heavy traffic, crowded spaces, and remote locations due to the higher risk of undetected bomb placement. Even places with high military presence can be targeted for their symbolic value.
Step-by-step explanation:
When looking for roadside bombs, vigilance is crucial in various circumstances. Situations that particularly warrant increased awareness include areas with recent terrorist activities, indicating an elevated threat level where attacks such as bombings may be more likely. Moreover, areas with heavy traffic and crowded areas are also high-risk zones, as they are often targeted to maximize impact. Remote areas with little to no traffic can also be dangerous, as the isolation may make it easier for terrorists to plant bombs without detection. Lastly, while one might assume that areas with high military presence are safer due to heightened security measures, these locations may actually be targeted due to their symbolic value and potential for causing significant disruption to military operations.