This is a question address canonicalization and parsing. Essentially what you're talking about is handled through a gazetteer (geographical rule set). There are two ways to do this right,
address_standardizer from the PostGIS project and certainly better if you're only using United States addresses.
pgsql-postal may be a better method for international addresses.
I'll show the address standardizer version for the address,
Chicken Ranch
10511 Homestead Rd
Pahrump, NV 89061
Using standardize_address from address_standardizer, returns a composite type of stdaddr
SELECT * FROM standardize_address('us_lex',
'us_gaz', 'us_rules', '10511 Homestead Rd, Pahrump, NV 89061');
building | house_num | predir | qual | pretype | name | suftype | sufdir | ruralroute | extra | city | state | country | postcode | box | unit
----------+-----------+--------+------+---------+-----------+---------+--------+------------+-------+---------+--------+---------+----------+-----+------
| 10511 | | | | HOMESTEAD | ROAD | | | | PAHRUMP | NEVADA | USA | 89061 | |
(1 row)
So you can see, ROAD is pulled out in suftype
Based on this q/a