Ergo, Dallas is likely correct. Even with all the new laws coming down about weed becoming legal, the municipalities will just buy these new machines, whether or not THEY are also accurate and do the job they are "supposed to do."
That does not seem to ring true in analysis. As weed gets more and more accepted in the country, there will be more shops that will be able to sell the product, which will increase demand, so the "weed-growing-sector", if it is tradable, should start rising. No?
They will buy a $500 breathalyzer because they are available and they are expected to do it, just like you suggested.
But they will also do it because of the easy revenue. Cities are not interested in governing for the masses as much as they are interested in governing for themselves.
A DUI will set you back $10k plus court costs, legal expenses, higher insurance etc...
I expect a marijuana charge will be the same.
So, they buy one breathalyzer for $500 and get a marijuana conviction for driving impaired with a 50 percent conviction rate for every charge produced. One breathalyzer will last several years. Do the math.....it'll pay for itself with the first conviction and keep 'giving'.
A city that charges its people .05 for plastic bags and .25 for plastic bottles won't have any problems charging people 10K for impaired driving regardless of how unreliable the breathalyzer is.