Dust is a health concern because of its potential to contain respirable particles, especially particles less than 10 microns in diameter (PM10). It is also a nuisance issue for residents living in the vicinity of unbound, unsealed (gravel) roads. Numerous techniques are used in attempts to reduce the dust generated from unbound roads, but all have limitations. Anecdotal evidence suggests that dust from unbound roads can be reduced for roads that incorporate a geotextile separator. A program to document the effect of the geotextile separators quantitatively is under way, with several test sections in central Missouri. A test section including a nonwoven, needle-punched geotextile; a non-woven, spun-bonded geotextile; and a new aggregate-only layer was installed; dust measurements were made over a 6-month period, during which the road experienced more than 3,600 vehicle passes. Dust levels were lowest immediately following the placement of new aggregate for the unbound layer and increased with time (traffic passes). Initially the sections containing a geotextile separator produced slightly less dust than the control (no geotextile) section. After 6 months of service, dust levels from the geotextile and control sections were similar, but the percentages of fines in the unbound layer above the geotextiles were about one-half that in the control section. Geotextile separators are likely to reduce dust for unbound roads when the source of particulate is fines migrating from the subgrade into the unbound layer. When the fines are developed because of degradation of the aggregate in the unbound layer, geotextile separators may be less effective in reducing dust from the roadway.