Thank you for your question: Unfortunately, there is no published study linking specific levels for this drug and driving performance.
However, these two studies taken in combination would help give some information: Both looked at the effect of a single dose. The first looks at the levels, and the 2nd looks at pyschomotor performance.http://www.ncbi.nlm.nih.gov/pubmed/1968715
Following a 1 mg dose, the average maximum concentration was 54.7 ng/ml (0.05 mg/L). Following a 2 mg dose, the average maximum contentration was 98.6 ng/ml (approximately 0.1 mg/L)
Your levels are not significantly higher than those seen with usual doses of this medication.http://trid.trb.org/view.aspx?id=674117
In this study, 2 different doses 0.25 mg and 1 mg of this medication did not have any effect on pyschomotor performance. At both of these doses (including the 1 mg that gave peak levels 1/2 of that which you had), no effects on driving would be expected.
Overall - these two studies would seem to suggest that there may not be a significant effect on driving WHEN USED ALONE.
It should be remembered, that medications that influence driving performance are additive or worse. Combining this medication with other medications, alcohol or even common over-the-counter medications used to treat allergies etc could cause significantly more important effect on driving than either medication.
I hope this has bee helpful.