In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: A driving simulator ( Transport Research Laboratory ) was used to measure reaction time ( RT ) , speed maintenance and steering accuracy .
### Output Text:
A driving simulator ( Transport Research Laboratory ) was used to measure reaction time ( RT ) , speed maintenance and steering accuracy . 