Walt's car is a well-used 2003 Pontiac Aztek, repainted a pale non-factory dull-green chosen by series creator Vince Gilligan perhaps to mimic a faded original paint job and thus symbolize Walt's previous bland existence. The windshield has been broken and replaced several times due to catastrophes both great and small, all traceable to Walt's descent into the drug world. Though Pontiac's Aztek was widely derided as ugly, overpriced and beset with quality issues (it never met sales quotas), it has built a loyal following for its versatility and is considered something of a good used-car deal - a deliberate analogy maybe to Walt's survival skills in his dangerous second career. The show's production keeps at least 2 Azteks equipped for different filming situations.
When characters on the show are smoking meth, they are actually smoking sugar or rock candy but do not inhale.
Characters and their values are represented by the colors they wear. Skyler is usually dressed in blue and Jesse in yellow and red (when he is in recovery, he wears gray). Walter wears green because he is stuck between his family and the drug trade. When the Whites' daughter is born, pink is introduced to the spectrum. Similar color patterns show up during the series. The DEA agents, Hank and Gomez, wear orange, representing police. Marie is usually in purple and many of the other doctors on the show are seen in it as well. And Jane, the recovering heroin addict, wears black.
The title of the series is spelled using the chemical symbols for bromine ("Br"), and barium ("Ba"). Chemical symbols from the periodic table of the elements also appear in every name in the opening credits: a single capital letter, or letter-pair with only the first letter capitalized (in line with scientific convention), shown in a differing color.
The actor who portrays Walter Jr. in the series (RJ Mitte), actually has cerebral palsy like his character on the show. However, his real life affliction is much milder than his character's, and he had to learn to walk with crutches and slow down his speech to play the part.