## 2 Materials and Methods
### Experimental Procedure
#### 2.2.7 Simulated Vehicle Experiments  
For simulated vehicle experiments, approximately 3 g of Sr-85 contaminated particles was applied to each testing surface with a surface area of 12.5 cm \(\times\) 15 cm (using a template to maintain repeatable particle coverage). Four (4) contaminated surfaces without the application of any stabilization technologies were prepared for each testing surface as NSCs. Uncontaminated surfaces served as blanks for background measurements. After the surface was contaminated with Sr-85, a stabilization technology solution was sprayed onto the contaminated surfaces (Figure 6A) and allowed to dry in the tent (drying time ranged from overnight to 3 days, as the surfaces did not all seem to dry completely overnight). CaCl\({}_{2}\) and Soil\({}_{2}\)O solutions were sprayed using a two-gallon multipurpose pump-up Scotts sprayer with the cone spray setting (Item 190498, [[https://www.scotts.com](https://www.scotts.com)]([https://www.scotts.com](https://www.scotts.com)), accessed on 9 April 2022). Phos-Chek MVP-Fx solution was sprayed using a 0.5-gallon multipurpose handheld pump-up sprayer (Item 56167, [[http://www.harborfreight.com](http://www.harborfreight.com)]([http://www.harborfreight.com](http://www.harborfreight.com)), accessed on 9 April 2022) because the other sprayer would quickly clog while using Phos-Chek MVP-Fx. Four (4) contaminated surfaces with each stabilization technology were prepared for each testing surface material. A small wagon (Model # H-2547; deck size: 24'' \(\times\) 48'', load capacity: 3000 lb; wheel type: 16'' pneumatic; [[https://www.uline.com/](https://www.uline.com/)]([https://www.uline.com/](https://www.uline.com/)), accessed on 9 April 2022) fitted with pneumatic tires with tread comparable to applicable vehicle tires (Figure 6B) was loaded with 800 lb of concrete parers that generated a contact pressure similar to applicable vehicles with downforce of 2000 lb. The evaluation testing for one testing surface material was set up under four tires simultaneously (Figure 6C). The wagon was manually pulled to move across contaminated/stabilized surfaces, as shown in Video S1 in Supplemental Information. The radiological activities of the contaminated/stabilized surfaces were measured before and after simulated vehicle rolling.  
The contaminated surfaces were replaced with uncontaminated surfaces, and the wagon was pushed backward across the uncontaminated transfer surfaces. The radiological activities of the previously uncontaminated and post-traffic contaminant transfer surfaces were measured to evaluate the magnitude of Sr-85 transfer. The radiological activities of Sr-85 from the tires having contacted the center of the contaminated/stabilized surfaces were measured to quantify the residual of Sr-85 contaminated particles on the tire. All measurements were done using an NaI spectrometer with different customized stand frames made of Plexiglass(r) to ensure a constant distance (1.27 cm) between the detector and the measured surfaces. For testing experiments on sand surfaces, both contaminated/stabilized and transferred surfaces were prepared by filling a 25 cm \(\times\) 25 cm template on a piece of Herculite(r) plastic sheeting (Emigsville, PA, USA) with equal amounts of premeasured sand. Then, the sand surfaces were contaminated/stabilized the same way as the concrete and asphalt parers. The same rolling procedures were applied to sand surfaces, and the corresponding measurements were performed.  
Figure 6: Spravers Used in Study (**A**), Wagon Used to Simulate Applicable Vehicle (**B**), and Simulated Vehicle Tire (**C**).