coordination
Explanation
The Joke
A passenger in a taxi (apparently a teacher or professor, since they need graph paper for their students) asks the driver if there is a convenience store nearby. The driver gives directions using what seem like numerical coordinates or distances. However, the driver fails to specify a coordinate system or reference frame for these directions.
This leads to a spectacular crash, after which the passenger -- bruised but still pedantic -- complains that the driver did not specify a coordinate system. The joke is that giving numerical directions without establishing a shared frame of reference is meaningless, and in this comic, it leads to literal physical disaster rather than just confusion.
The Humor
The humor plays on the gap between how ordinary people give directions (casually, with landmarks and rough distances) and how a mathematician or physicist would want them (precisely, with a defined coordinate system and reference frame). The passenger is the stereotypical academic who cannot let an imprecise statement go uncorrected, even after a car crash. The comic also plays on the word "coordination" in the title -- both the mathematical concept of coordinate systems and the everyday meaning of coordinating actions to avoid crashing into things. The escalation from a simple request for directions to a fiery wreck is classic SMBC absurdist escalation.
References
In mathematics and physics, a coordinate system is a framework that uses numbers to uniquely determine the position of points in space. Without specifying the origin, axes, and units of a coordinate system, numerical coordinates are meaningless. This is a fundamental concept in linear algebra, analytic geometry, and physics.