Cobb County just participated in a local SPLOST election, where "based on complete but unofficial results, 42,971 people voted in the election: 21,525 for the SPLOST and 21,446 against, a difference of 79 votes." In a county census-certified at 688,078 residents, 6.2% of the people voted in an election to decide whether to incur a $492,000,000 sales tax over the next five years; the resulting decision (79 votes) represents 0.01% of the population. Regardless of the merits of the decision, it is both daunting and embarrassing that such a far-reaching decision is made by such a minority of the citizens.
It might be worth combining single-ballot elections into a greater election cycle - bringing minor elections like these into typical Primary or General Elections held in May and November of the year. You would certainly get a greater cross-section of the population through larger voter turn-out. However, you might end up with people voting without knowledge of the issue, similar to how we randomly pick judges on a ballot without any idea who they are (this certainly favors names at the beginning of the alphabet and ones that have a nice sound to them). Those who voted yesterday were certainly more informed and interested in the ballot measure based upon the fact that they came to the polls at all.
Regarding the merit of the vote itself, I would caution against the knee-jerk no-taxes concept that citizens throughout the U.S. are naturally drawn to. Some portion of the projects slated to be built would be shelved without the SPLOST money. However, a vast majority of them are geared towards Transportation improvements designed to improve our quality of (driving) life and enhance the livability and economics of being a resident, employee and employer within our County. If this SPLOST would have failed to pass, these projects would be funded through the County General Fund, being paid by our property taxes, which in themselves would need to be increased to cover these expenses. If one has the option, it is better to spread the tax burden out to continual transactions of the millions of people passing through the County on a day to day basis rather than on the yearly property tax bill of the much smaller pool of property owners within the County. This was a good decision, and the County has proven themselves generally responsible for their coffers (not including the County Board of Education, a continual source of local embarrassment).