The Modus is B-Class car and was the first such car to get a 5-star rating in the EuroNCAP tests. Volvos, on the other hand, have a long standing and largely deserved reputation for safety. While modern small cars may indeed sustain a substantial amount of damage in a crash as they dissipate the energy, they tend to do a very good job of protecting occupants. One other thing to keep in mind in such mixed crashes is that while the larger vehicle may have more momentum, the lighter car can also be shoved out of the way to some degree, also dissipating energy. Fifth Gear did a 40mph frontal offset test with the Renault and Volvo (that's an 80mph closing speed) and you can check out the video after the jump. There's also a video of a Smart ForTwo doing a similar crash with a Mercedes E-Class, with similar results. Don't be afraid to think small, it probably won't kill you.
[Source: YouTube, via Trollhattan Saab]