Distance allows for more than one 1-88

Q. How are interstates numbered and named? While driving in the state of New York, I saw an I-88 there, too.

--J. B., Lisle

A. There is, indeed, another I-88 in New York. It's about 130 miles long, and runs between Binghamton and Schenectady.

Doug Hecox spokesman of the Federal Highway Administration in Washington, D.C., says interstates were numbered according to a pattern when the system began to be built in 1957.

"North-south roads were given odd numbers, and east-west roads were given even numbers," said Hecox.

Additionally, principal north-south routes were usually given numbers ending in 1 or 5, and principal east-west routes were given numbers that ended in zero.

"The numbering of roads began in the southwest, and moved east and north across the country," said Hecox.

This is I-10 crosses the south and I-90 crosses the northern part of the country.

Later, three-digit numbers were used for shorter sections or bypass routes, usually by adding a multiple of 100 to the original interstate being bypassed. So, I-294 is a bypass for I-94, and I-355 is a shorter section branching off of I-55.

In order to get more federal funds for their roads, occasionally a state decides to lump an existing state route into the interstate system, said Hecox.

States, however, then have to meet federal interstate standards, including making the road wider and stronger to handle higher traffic volume.

This was the case when old Illinois Route 5 -- the former east-west tollway we now know as the Ronald Reagan Memorial Tollway -- became I-88 in 1990.

"Based on our numbering conventions, we simply ran out of numbers," said Hecox.

"Since there wasn't any other logical number to pick, and the first I-88 in New York was enough away from Illinois so as to not confuse drivers, we decided to give another segment of the interstate system the number 88 as well."

Giving interstates honorary names, such as Ronald Reagan Memorial Tollway, is done by state legislatures.