Yellow foxtail or bristle grass is a summer annual grass. It is one of the most common foxtail species found in home lawns. 

Since it's an annual, it produces an abundance of seeds before it dies for the winter. The seeds lay dormant in the soil until the right weather conditions and soil temperatures arrive for them to germinate. If you can remove the seed heads now, it will help reduce the number that will fall into the soil. 

These look like they are nearing the time to let go of the seeds, so either hand pulling/digging, or using a string trimmer to scalp the plants low will help to cut down on seeds. The link above also lists some herbicide options. Foxtail thrives in hot sun and takes advantage of gravelly soils, which is why it popped up along pavement. Using the soil is rocky from the prep work for laying hard surfaces, plus it will get the reflective heat off the pavement. 

Once you remove the plants, you can add some organic matter to the area and overseed with the desired seed mix. If the foxtail is throughout the lawn area, mow at a low setting and bag the clippings to help contain the seed heads, then aerate and overseed to help thicken up the turf growth. Next spring, you can apply a preemergent to help keep the seeds from germinating. 

Mowing at the highest setting once the grass thickens is a good practice to help prevent weed seeds from establishing in lawns. 

Let us know if you have further questions, 

Emily