The number of campaign commercials for the 2012 elections is on track to far exceed what ran four years ago, according to Kantar Media. A tally taken four weeks before Election Day found that campaign ads had run on local television and national cable more than 2.7 million times, compared with 3.5 million in all of 2008.

Experts consider volume to be a more accurate gauge of an advertising war’s intensity than money spent because advertising rates vary widely from city to city. A $1 million buy in Madison, Wis., for example, is not the same as one in Miami.

The more than $3 billion that Kantar Media estimates will be spent on political advertising this year is roughly equal to the amount set aside in a government settlement with major banks to help homeowners who owe more than their homes are worth.

In the presidential race alone, the campaigns and their allies have reserved about $70 million in commercial time between Oct. 15 and Election Day. Of that, $5 million is just for Nevada and its six electoral votes. Even larger amounts are being spent in places like Ohio and Florida, where the high cost of advertising gives campaigns and super PACs less punch for their dollar.

But Nevada, with its relatively low advertising rates and just two media markets that reach most of the state, is beating even the most hotly contested battlegrounds in the number of ads broadcast. Reno, the state’s No. 2 market, ranks fourth in total saturation, just behind Cleveland (second) and Denver (third).

“There are battleground states, and then there’s Vegas,” said Ken Goldstein, president of the Campaign Media Analysis Group at Kantar Media.

“We have a joke around here,” said Lisa Howfield, the general manager of KSNV, the NBC station. “Pretty soon we’re going to have such long commercial breaks that people are going to tune in and all they’ll hear is: ‘Hello, welcome to News 3. And goodbye.’ ”