How are sisterhood and loyalty established?:
In both Thelma and Louise and Set it Off, the main characters are already good friends. Thelma and Louise talk to each other on the phone and are vacationing together over a weekend. Stony, Cleo, TT and Frankie grew up together in the projects; after Frankie gets fired from the bank, all of them work together, and they all party together. Thus, in a way, they are all already sisters. However, the bonds of sisterhood and loyalty are deepened when tragedy strikes.
In the case of Thelma and Louise, the women become bonded when Harlan attempts to rape Thelma. Louise (we guess based on allusions made to the incident in 'Texas') was a rape victim herself and was manhandled by the criminal justice system. When she came upon Harlan attempting to rape Thelma, all of that hurt, anguish, and distrust came back. Louise was victimized twice over (once by her perpetrator and once by the system)...and she couldn't let that happen to her good friend. In that split-second decision to squeeze the trigger, Louise killed Harlan as much for herself as she did to protect Thelma. And in doing so, they were bonded for life -- not only because they were both victimized, but because they took control by fighting back, thus making them survivors. While Thelma still had a way out (she wasn't the one who pulled the trigger), she recognized the depth of Louise's sacrifice and stayed on for the ride of her life. Thelma was able to repay Louise's loyalty by robbing the convenience store for gas money, thus making her as much of a criminal as Louise. In the end, these women recognized that the deepest bond they ever had was formed when they sacrificed everything for each other -- they were sisters as they drove off that cliff together.
In Set it Off, the bonds of sisterhood run deep in the projects. These women grew up together, ran together, and got in trouble together. Even when Frankie got her job at the bank (thus getting out of the ghetto life), she still spent her time hanging out with Cleo, TT, and Stony, who were all still living in the projects -- they were her people and they always would be. Loyalty also runs deep -- when Stevie was shot and killed, the women stuck together and comforted one another, since there was no one else: they only had each other. The system also victimized this group of women not once, but twice: when persecuting Frankie for knowing the robber and for killing innocent Stevie. When the women decide to fight back (by screwing the system that screwed them), the bond between them is solidified -- they become partners in crime in order (which requires deep trust) in order to achieve the same basic goal: to get enough money to get out of the projects. These women wouldn't rat on each other if given the chance. And three of them died in their pursuit of a better life for themselves and each other -- that is sisterhood and loyalty.
Why is Set it Off a Road Movie?:
The road, as we have learned is a physical entity -- pavement beneath the wheels of our vehicle for the purpose of guiding our way to and from our destinations. The road can also represent upward movement -- overcoming one's stationary status and becoming more than what one currently is. The 'road' can also be a metaphor for a psychological journey out of one's current mental status into another. It is in these latter two that we find Set it Off. Set it Off is, ultimately, a film about four women from the 'hood who were screwed over by the system in every way who were trying to get more money in order to get out of the ghetto. They wanted upward movement in terms of social and financial status. Thus, their road was less about traveling a great distance and more about getting across town to a better neighborhood and a better life. They attempted to achieve this by criminal means, since that was the only option left for these women -- all other avenues to their destination failed to get them out.
In the end of the film, Stony was the only one who remained alive -- and with a large portion of their stolen money. She had the money to achieve that upward movement, but it was tempered with the anguish that comes from the high price she paid (the loss of her 3 best friends). But, as the montage at the end indicated, these sisters wanted a better life for each other. Thus, Stony had to make the psychological journey out of guilt for the deaths of her friends and move towards honoring their sacrifice by living the better life they so desperately wanted.
The pursuit of upward movement and psychological movement can be a journey as epic as traveling a great distance. Thus, Set it Off can fit in the road movie genre.