Despite oodles of computers, legions of statisticians and forms of every kind, the government has no idea -- none whatever -- how many of its workers travel on official business. Or where they go, or why. Who travels, and how often. Or what they spend. Best guess of minimum of $2 billion a year.

What is known, however, is that sugar daddy though he may be, when it comes to expense accounts Uncle Sam is something of tightwad, except for his VIPs.

With that background, be advised the Carter administration is supporting a bill -- just cleared by the House Government Operations Committee -- to raise the regular per diem from $35 to $50, and boost the high-cost city allowance from $50 to $75.

The bill by Rep. John Burton (D-Calif.) also would allow the government to pay travelers up to 25 cents a mile for driving their cars on company business. The current maximum is 20 cents, although the General Services Administration estimates it costs about 21.5 cents to drive a typical car one mile these days.

With inflation hitting everything from hotel and motel rates to taxi fees, the government has been forced to poke holes -- 159 to be exact -- in the current $35 standard per diem. There are now 159 cities and areas (Washington is one of them) where government travelers can be reimbursed for actual expenses up to $50 a day. The Burton bill would boost the standard per diem from $35 to $50, and the special rate payment from the $50 maximum to $75.

The high cost of traveling for Uncle Sam is causing both budget and morale problems in some agencies. A growing number of people who are supposed to travel on official businesses are refusing to take assignements, and many who do are staying with friends, and living off Big Macs when away from home.

Not too long ago the General Accounting Office got a sticky wicket case from one of the government's super-secret operations. Seems a gentleman was detailed to another city for an extended period of time. To save money, he moved in with his parents.

Mom and Pop, figuring him for a high-paid G-man, charged their federal son rent. He passed the bill on to his agency which, in best government traditions, bucked it up to GAO. GAO ruled that living with your folks -- unless they manage a Hilton or Hyatt Hotel -- is not reimbursable.

The National Treasury Employees Union deserves a lot of credit for birddogging Uncle Sam to come up with more travel money. NTEU has lots of members -- IRS types and the like -- who travel a lot.

NTEU, which will sue at the drop of a hat, filed a complaint in federal court recently asking that the government raise the mileage allowance. At the time it was a maximum of 18.5 cents a mile. Before the court got rolling, however, General Services Administration raised the mileage allowance to a maximum of 20 cents a mile.

If the Burton travel bill becomes law, insiders expect GSA again will quickly move to raise the mileage allowance. That in turn will cause many private firms, who follow the federal per diem guidelines, to boost payments to their employes.