Peer pressure plays a significant role in teen passenger behavior, particularly in the context of risky driving activities. Teens are often influenced by their peers to engage in behaviors such as speeding, not wearing seatbelts, or participating in distracted driving activities. For example, a study conducted by the AAA Foundation for Traffic Safety found that teenage drivers were more likely to engage in risky behaviors when driving with their peers compared to when driving alone.

Furthermore, peer pressure can also impact a teen's willingness to speak up against unsafe driving practices. In a survey conducted by the Centers for Disease Control and Prevention, many teens admitted to feeling uncomfortable speaking up when the driver was engaging in risky behaviors due to fear of social repercussions from their peers.

References:

1. AAA Foundation for Traffic Safety. "Teen Driver Risk in Relation to Age and Number of Passengers." https://aaafoundation.org/teen-driver-risk-in-relation-to-age-and-number-of-passengers/
2. Centers for Disease Control and Prevention. "Teen Drivers: Get the Facts." https://www.cdc.gov/transportationsafety/teen_drivers/teendrivers_factsheet.html